Title:
CONTROL VALVE ARRANGEMENT FOR A HYDRAULIC DRIVE
United States Patent 3800669


Abstract:
First and second control units, having first and second control valves, are provided for connecting first and second pumps with a plurality of hydraulic first and second consumer motors, respectively. The units also include first and second switching valves which can be operated to supply pressure fluid from the respective first or second pumps to the second and first consumer motors, respectively, so that each consumer motor can be also operated with pressure fluid from both pumps.



Inventors:
DISTLER J
Application Number:
05/275829
Publication Date:
04/02/1974
Filing Date:
07/27/1972
Assignee:
REXROTH G GMBH,DT
Primary Class:
Other Classes:
60/421, 91/530
International Classes:
B62D11/18; E02F9/22; F15B11/17; (IPC1-7): F15B13/06
Field of Search:
91/411R,414 60
View Patent Images:



Primary Examiner:
Geoghegan, Edgar W.
Attorney, Agent or Firm:
Striker, Michael S.
Claims:
I claim

1. Control valve arrangement for a hydraulic drive comprising at least one hydraulic first consumer motor, at least one hydraulic second consumer motor; a first control unit including a first source of pressure fluid, and at least one first control valve for controlling the flow of fluid from said first source to said first consumer motor; a second control unit including a second source of pressure fluid, at least one second control valve for controlling the flow of fluid from said second source to said second consumer motor, a pressure conduit connected with said second source, and a switching valve located in said pressure conduit downstream of and connected in series with said second control valve, said switching valve being also connected with said first consumer motor and being movable between a normal position, and at least one control position for connecting said second source with said first consumer motor whereby said first consumer motor can be operated by pressure fluid from said first source alone or by pressure fluid from said first and said second sources; and another switching valve in said first control unit and connected with said second consumer motor of said second control unit, and movable between a normal position, and a control position for connecting said first source with said second consumer motor whereby said second consumer motor can be operated by pressure fluid from said second source alone or by pressure fluid from said first and said second source.

2. Control valve arrangement as claimed in claim 1 wherein said first and second control valves are connected in parallel between the first and second source, respectively, and a low pressure discharge region.

3. Control valve arrangement as claimed in claim 1 and comprising means for operating said switching valve of said second control unit to move to said control position at a time different from the time at which said first control valve is operated.

4. Control valve arrangement as claimed in claim 1 comprising two first consumer motors; wherein said first control unit includes two first control valves for controlling the flows from said first source to said first consumer motors, respectively, each first control valve being movable between an inoperative position and at least one operative position; and wherein said switching valve has two control positions respectively directly connected with said two first consumer motors.

5. Control valve arrangement as claimed in claim 1 wherein at least said second control unit includes a substantially cylindrical valve body formed with an inlet for pressure fluid at one end, and with an outlet to a low pressure region at the other end, with consumer conduits connected with said second consumer motor, with diametrical valve cylinder bores, and with duct means connecting said inlet, said outlet, said consumer conduits and said bores, each valve of said control valves and switching valve including a valve slide located in one of said diametrical valve cylinder bores and having piston portions, said valve body having annular chambers cooperating with said piston portions connected with said duct means and surrounding said valve slides for establishing different connections of said duct means between said inlet and outlet, and said consumer conduits when said valve slides are displaced.

6. Control valve arrangement for a hydraulic drive comprising at least one hydraulic first consumer motor and at least one hydraulic second consumer motor; a first control unit including a first source of pressure fluid and at least one first control valve for controlling said flow of fluid from said first source to said first consumer motor; and a second control unit including a second source of pressure fluid, at least one second control valve for controlling the flow of fluid from said second source to said second consumer motor, and a switching valve connected with said first consumer motor and movable between a normal position, and at least one control position for connecting said second source with said first consumer motor whereby said first consumer motor can be operated by pressure fluid from said first source alone, or by pressure fluid from said first and said second sources; at least said second control unit including a substantially cylindrical valve body formed with an inlet for pressure fluid at one end, and with an outlet to a low pressure region at the other end, with consumer conduits connected with said second consumer motor, with diametrical valve cylinder bores, and with duct means connecting said inlet, said outlet, said conduits and said bores, each valve of said control valves and switching valve including a valve slide located in one of said diametrical valve cylinder bores, said valve body having annular chambers including a pair of first annular chambers communicating with said pressure inlet and surrounding the valve slide of said switching valve, a pair of second annular chambers communicating with said second consumer motor and surrounding said valve slide of said switching valve adjacent said first annular chambers, respectively, said valve slide being shiftable to connect said first and said second annular chambers, and a third annular chamber connected with said outlet and surrounding said valve slide of said switching valve, said duct means including a connecting channel connecting said second annular chambers in the normal position of said switching valve, and another channel connecting said third annular chamber with said inlet, said channels being located in different planes, and a duct connecting said channels.

7. Control valve arrangement as claimed in claim 6 wherein said valve cylinder bore of said switching valve has a widened portion between said first and second annular chambers forming an annular gap with said valve slide of said switching valve connecting said first and second annular chambers and constituting said duct connecting said channels in all positions of said valve slide.

Description:
BACKGROUND OF THE INVENTION

The present invention relates to a control valve arrangement for the hydraulic drive of a machine such as a dredging apparatus. Control valve arrangements are known in which the pressure fluid from two different pumps are supplied through two control units to two groups of hydraulic consumer motor which operate different parts of the machine. In the prior art, both pumps can be connected with a specific hydraulic motor. Due to this fact, the efficiency and power of a dredging machine can be substantially increased, and moreover the two pumps or other sources of pressure fluid, are economically used.

The connection of one pressure source to a consumer motor which is already supplied with pressure fluid from another pressure fluid source, is carried out in the prior art by connecting conduits for connecting the outlet of one control valve with the inlet of the following control valve which is associated with the respective consumer motor. The control valves must be large, since they have to control the double amount of pressure fluid. The cost of such an arrangement is high, and storage of different types of valves and additional tools are required.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a control valve arrangement which includes inexpensively and easily manufactured control valve units for driving hydraulic consumer motors with pressure fluid from one or two sources of pressure fluid.

In accordance with the invention at least one control unit of two control units which are connected with different pressure sources, has an additional switching valve which can supply pressure fluid from one source to a consumer motor supplied with pressure fluid from another source by means of a control valve. Due to the direct connection of the pressure source of the respective other control unit to the respective consumer motor, the control valve associated with the respective consumer motor, need not be enlarged, so that the control valves and switching valves in each control unit may have the same size.

The use of an additional switching valve for supplying pressure fluid from a first source to a consumer motor supplied by a second source by means of a control valve in the respective other unit, results in a considerably reduced cost, as compared with the corresponding arrangement according to the prior art.

In a preferred embodiment of the invention, the additional switching valve is the last valve in the respective control unit in downstream direction of the pressure fluid, and is connected in series with the preceeding control valve of the respective control unit. In this manner, the respective switching valve can only connect the associated pressure source with a consumer motor which is normally supplied by the other source, if the upstream control valves permit such a pressure fluid supply. When an upstream control valve of the same control unit is operated to supply pressure fluid, the flow of pressure fluid to the additional switching valve, which is arranged downstream of the respective control valves, is interrupted.

It is advantageous to use as control valves and switching valves, valve means which have a normal position of rest and two control positions, and whose valve body has six ports. The control valves, but not the additional switching valves, of each control unit, are connected in parallel with each other between the respective pressure source and a low pressure discharge region such as a container with atmospheric pressure.

It is also advantageous when the series connected additional switching valve is operated at a different moment than the respective associated control valve of the respective other control unit. Due to this timed sequence, the fine adjustability of the hydraulic drive is not impaired by adding the flow of pressure fluid of the second source of pressure fluid.

In a specific embodiment of the invention, the additional switching valve has two control positions respectively connected with different consumer motors associated with the respective other control unit. In this event, the respective additional shifting valve is associated with two hydraulic motors which are, in turn, supplied with pressure fluid from two control valves of the respective other control unit. This has particular advantages if the control valves of one control unit are associated with the cylinders of the consumer motors for the scoop and the boom of a dredging machine. For increasing the working speed, the second source of pressure fluid is connected with the working chambers of the two consumer motors.

A particularly simple and advantageous construction of the control units is obtained if either chambers which communicate with the pressure source, and are located adjacent other annular chambers connected with consumer conduits, are connected by a channel which is located in another plane than a channel which is located between the chambers which can be connected with the pressure source. This results in the possibility to arrange the valve slide of the switching valve either in series or in parallel with the respective upstream slides of the control valves.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view illustrating the hydraulic circuit of a control valve arrangement according to the invention which is particularly suited for a scoop dredging machine;

FIG. 2 is a longitudinal sectional view illustrating a control unit used in the embodiment of FIG. 1; and

FIG. 3 is a fragmentary sectional view illustrating a modification of the control unit shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, a first pump or other source of pressure fluid PI supplies pressure fluid through a control unit I to hydraulic consumer motors F1, L and AT. A second pump or source of pressure fluid PII supplies pressure fluid through a second control unit II to hydraulic consumer motors Fr, SCH, and S.

Control unit I includes control valves 1, 2 and 3 and a switching valve 4, and control unit II includes control valves 5, 6, 7 and a switching valve 8. The hydraulic motors are used for operating a scoop dredging machine. Control valve 1 controls the left drive motor F1, control valve 2 controls the scoop drive motor L, and control valve 3 controls the boom drive motor AT. The operating conduits A and B of the switching valve 4 are directly connected with the beam drive motor S, which is primarily controlled by the control valve 7 of the control unit II. The control valve 5 of control unit II controls the right drive motor Fr, the control valve 6 controls the tilting drive motor SCH, and control valve 7 controls the beam drive motor S independently of the positions of the control valves 5 and 6.

The additional switching valve 8 of control unit II is connected by its operating conduit A' directly with a cylinder chamber 9 of the hydraulic consumer motor L, and operating conduit B' is directly connected with the cylinder chamber 10 of the hydraulic consumer motor AT. Each of the control valves has three positions a, b, c, for connecting three pairs of ports with different connections. All valves are shown in the normal position b in which connection between pump PI and pump PII with the respective hydraulic motors is interrupted while the pumps PI and PII are respectively connected with an open container T or other low pressure discharge area. In the two other operative positions a and c of the control valves 1, 2, 3, 5, 6, 7, the respective associated consumer motor is supplied with pressure fluid from pump P1 and pump PII, respectively, the flow being reversed when the control valve is shifted from the position a to position c, as indicated by arrows. The actual construction of the control valves will be explained hereinafter with reference to FIG. 3.

In the control positions a and c of switching valve 4, the operating conduits A and B of switching valve 4 are connected with the cylinder chambers S1 and S2 of the hydraulic motor S so that pressure fluid from the first pump PI is supplied to the hydraulic motor S which is primarily driven by pressure fluid from the second pump PII. In the same manner, the switching valve 8 connects in the two control positions a and c, to the operating conduits A' and B' which supply pressure fluid from the pump P11 to a cylinder chamber 10 or 9 of the hydraulic motors AT, L which have a piston and piston rod 12 and 11. As explained above, hydraulic motors AT and L are primarily controlled by control valves 3 and 2 respectively which direct pressure fluid from pump PI to said motors.

In the control position a of switching valve 8, the pressure source PII is connected by operating conduit B' with the cylinder chamber 10 on one side of piston 12 of motor AT, while in the position c, pump PII is connected by operating conduit A' with cylinder chamber 9 of motor L. When control valve 2 is shifted to the position a, while the switching valve 8 is placed in the control position c, hydraulic consumer motor L is supplied with pressure fluid from both pumps PI and PII to cause an outward movement of piston rod 12. When control valve 3 is shifted from the position b to the operative position a, and when tbe switching valve 8 is shifted from the position b to the control position a, the cylinder chamber 10 of the hydraullic consumer motor AT also receives pressure fluid from both pumps PI and PII so that the piston rod 12 is moved at an increased speed.

It is, of course, possible to connect the operating conduit A' of switching valve 8 with the cylinder chamber 13 on the other side of the piston 12 of the consumer motor AT, so that the consumer motor AT can be operated in both directions by both pressure sources PI and PII.

In the illustrated hydraulic circuit, it is not possible to connect both pumps to the consumer motors F1, Fr and SCH, but consumer motors L, AT, and S can be either operated by pressure fluid from one pump only, or by pressure fluid from both pumps, depending on the position of the switching valves 4 and 8.

In the illustrated normal position b of all control valves and switching valves, the respective pump PI or pump PII is connected with the discharge container T. If one of the control switches is shifted to an operative position a or c, the flow of pressure fluid to container T is interrupted, and the pressure fluid supplied to the hydraulic motor associated with the respective operated control valve.

The pressure ports p of control valves 1, 2, 3 of control unit I, are connected by a conduit 15 and branch conduits 15a, 15b directly with the pressure conduit 16 of the pump PI. The pressure ports p of control valves 5, 6, 7 are connected in the same manner by a conduit 19 and branch conduits 19a, 19b with the pressure conduit 20 of the pump PII. The pressure ports p' of the switching valves 4 and 8 are connected by conduits 17 and 21, respectively with connecting conduits 18 and 22, respectively which communicate with the pumps PI and PII respectively. Consequently, the switching valves 4 and 8 can only be connected with the pumps PI and PII when the control valves 1, 2, 3, and 5, 6, 7, respectively are in their normal positions of rest b. Conduits 25 and 26 connect other ports of the control valves 1, 2, 3 and 6, 6 7 with the discharge conduits 27. The control valves 1, 2, 3 are connected in parallel to pump PI, and the control valves 5, 6, 7 are also connected in parallel with the pump PII. The control valves and the switching valve of each control unit I and II are connected in series so that the switching valves 4 or 8 are connected with the pump PI or pump PII only when the control valves are in the normal position b. Switching valves 4 or 8 are separated from the pumps PI and PII, respectively when one of the control valves 1, 2, 3 or 5, 6, 7 are shifted out of the normal position of rest.

The shifting of the switching valve 4 for supplying pressure fluid from pump PI to the consumer motor S in addition to the pressure fluid of pump PII takes place a small time period after the associated control valve 7 has been operated to drive consumer motor S with the fluid from pump PII. In the same manner, the switching valve 8 is operated after operation of the control valve 3, or of the control valve 2 to supply fluid from pump PII additionally to consumer motors L and AT, respectively. Due to this arrangement, the fine adjustment of the consumer motors is not disturbed by the adding of the flow of pressure fluid by the pump of the respective other control unit.

As shown in FIGS. 2 and 3, respectively, each control unit I or II, has a cylindrical cast housing which is penetrated by four transverse bores 31, 32, 33 and 34. The bores 32, 33 and 34 receive the valve slides 35, 36, 37 which establish together with ports in the cylindrical bores, the control valves 1, 2, 3, or 5, 6, 7, respectively described with reference to FIG. 1.

The valve slide 38 received by the cylinder bore 31 constitutes the switching valve 4 or 8, respectively. The pressure fluid inlet P is provided at one end, and the discharge outlet T' is leading to the discharge container T is provided at the other end of the housing 30. The inlet P which is connected with one of the pumps PI and PII opens into a cavity 40 which communicates with two longitudinal channels 41 and 42 which connect annular chambers 43, 44, 45 and 46, 47, 48, respectively. Consequently, these chambers are filled with the pressure fluid. Other annular chambers 50, 51, 52 and 53, 54, 55 surrounding valve slides 37, 36, 35 are connected with operating conduits, not shown in FIG. 2 which are connected with the consumer motors.

Two channels 56 and 57, communicating with discharge outlet T' connect annular chambers 58, 59, 60, 61 and 62, 63, 64, 65, respectively.

In the illustrated normal position of rest b of the control valve slides 35, 36, 37, the annular chambers 50 to 55 are separated from the adjacent annular chambers which communicate with the discharge outlet T' and with the pressure inlet P.

The annular chambers 70 to 77 are connected by channels 78 to 81, and portions of the valve bores. Consequently, the pressure inlet P is connected with the pressure outlet T and circulation in the control unit can take place without pressure. The valve slide 38 of the switching valve 4 or 8 is surrounded by two annular chambers 87 and 88 which respectively communicate with the operating conduits A and B which are connected with the respective consumer motors. Adjacent the annular chambers 86 and 87 other annular chambers 88 and 89 surround valve slide 38. Chambers 88 and 89 are connected by a channel 90 which is located in another plane than the channel 81 which connects the chambers 75 and 77. Channels 81 and 90 are connected by a bore 91, so that in chambers 88, 89 the same pressure prevails as in channel 81, which is connected with the annular chamber 75.

When the valve slide 38 of a switching valve 4 or 8 is shifted in the direction of the arrow 93, the annular recesses of valve slide 38 connect the chamber 58 with chamber 86, and chamber 87 with chamber 89. At the same time, the communication between chambers 76 and 77 is interrupted, so that the free flow from the high pressure chamber 40 to the discharge outlet T' is interrupted, whereby in channel 81 and chambers 88 and 89 the pressure is increased to the pressure of the respective pump. Due to the connection of chambers 87 and 89 by the recess 95 of valve slide 38, the operating conduit communicating with chamber 87 is connected with the pump and due to the connection of the chamber 86 with the chamber 58 through the recess 94 of the valve slide 38, the operating conduit communicating with chamber 86 is connected with the discharge outlet T'.

If, for example, the valve slide 35 is shifted in the direction of the arrow 96, the connection between the annular chambers 75 and 74 is interrupted, so that channel 81 is separated from the pressure inlet P. The connection between channel 81 and the pressure source is also interrupted if the valve slides 36 or 37 of the respective control valves are shifted to one of the end positions thereof.

An effective control of the valve slide 38 is assured only in the illustrated position of the valve slides 35, 36, 37, since only in this position, the channel 81 which communicates with the annular chamber 77, is connected with the pressure inlet P. The annular chambers 43, 44, 45 and 46, 47, 48 of the control valve slides 34, 36, 37 are directly connected by the housing channels 100, 101, 102, 103 and are connected by channels 41, 42 in any position of the control valve slides with the pressure inlet P, and are connected in parallel, so that an effective shifting of one of these control valve slides, independently of the position of another control valve slide, can be carried out. If more than one valve slide is operated, the pressure fluid supplied through the inlet P is divided between the respective consumer motors.

Due to the fact that the connecting channel 90 is not directly connected with the housing channel 81, but by means of a transverse bore 91, the housing chambers 88 and 89 of the shifting valve slide 38 can be also directly connected with the pressure inlet, so that they are connected in parallel to the pressure source, together with the respective chambers of the other control valve slides. It is only necessary to devise a connecting bore 104 between the annular chambers 45 or 48 and the channel 90, instead of connecting channel 81 with the channel 90.

In FIG. 3, the connection between channel 81 and the connecting channel 90 is not obtained directly by a connecting bore, but indirectly by widened cylinder portion 98 forming an annular space 99 between valve slide 38 and portion 98. The annular space 99 connects housing chamber 77, which is connected with channel 81, with the annular chamber 88 which is connected by the connecting channel 90 with annular chamber 89.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of control arrangements for hydraulic drives, differing from the types described above.

While the invention has been illustrated and described as embodied in a control valve arrangement for operating consumer motors selectively with pressure fluid from one pump, or from two pumps, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.