US3077901A

US3077901A - Divided flow, control valve system

Info

Publication number: US3077901A
Application number: US39088A
Authority: US
Inventors: Ernst F Klessig
Original assignee: Vickers Inc
Current assignee: Vickers Inc
Priority date: 1960-06-27
Filing date: 1960-06-27
Publication date: 1963-02-19
Anticipated expiration: 1980-02-19
Also published as: GB951691A

Description

Feb. 19, 1963 E. F. KLESSIG 3,077,901

DIVIDED FLow, CONTROL VALVE SYSTEM Filed June 27. 1960 2 Sheets-Sheet 1 INVENTOR. ERNST F. KLESSIG ATTORNEYS Feb. 19, 1963 E. F. KLESSIG 3,077,901

DIVIDED FLOW, CONTROL VALVE SYSTEM Filed June 27. 1960 2 Sheets-Sheet 2 INVENTOR. ERNST E KLESSIG 3,077,961 DIVIDED FLOW, CUNTROL VALVE SYSTEM This invention relates to power transmissions, and is particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

The invention is more particularly concerned with a control valve system for controlling the operation of one or more fluid motors at will and for automatically unloading the pump when all motors are cut out of operation.

One such type of control valve system which has been widely adopted as, for example in mobile road machinery applications, comprises a plurality of directional control valves in side-by-side relationship to form what is known as a multiple valve bank such as exemplified by the pat cuts to Ber'glund, No. 2,289,567, issued July 14, 1942, and to Twyman, No. 2,247,140, issued June 24, 1941. In multiple valve bank systems of this type, a common pressure delivery or supply passage and a common return pas-sage utilized by each valve in the bank are connectable by each selectively operable control valve to a motor or motor ports of each individual valve in the bank. A by-pass or unloading passage which is interconnected to the pressure supply passage ahead of the first valve member also extends through the bank and remains open while all valves are in a neutral position, the pressure delivery passage being closed to all of the motor ports of the individual directional control valve, and thus unloading the pump through the by-pass passage. When any individual valve member is shifted to connect the pressure supply passage to a motor port of an individual valve member, the by -pass passage is closed.

Although control valve systems of this type have proved to be adequate for many applications, they do have some disadvantages, the main one being that the directional con trol valves have to be large in order to handle the full pump displacement through the unloading passage. Although it is convenient to place in the bank as many valves as are necessary for controlling the same number of fluid operated motors in the hydraulic transmisison system, in some instances where it is necessary to have a large num ber of valves in the bank, the total pressure drop across the valve bank becomes excessive, each valve being added to the bank, of course, adding to the pressure drop. This can be alleviated by increasing the size of the valves, but where there are a large number of valves in the bank, this greatly increases the size, weight, and cost of the control valve system. Also in such valve systems, although metering may be obtained by manual manipula tion of the control valves, no provision has been made for providing an accurately controlled, regulated flow from the same valve system for a fluid actuated device or devices requiring a regulated flow which in some cases is substantially less than the full pump displacement, the problem being aggravated because the pump in such systems is usually driven from a variable speed prime mover.

It is therefore an object of this invention to provide an improved control valve system of this general class which provides all of the advantages of the prior art types while avoiding the disadvantages.

It is also an object of this invention to provide an improved control valve system for controlling a fluid operated device or devices wherein the full capacity of the pressure fluid supply source may be utilized for operation of one or more of the fluid actuated devices and which 3,077,901 Patented Feb. 19, 1963 is adapted to provide a regulated amount desired quantity for the device or devices.

It is a further object of this invention provide an improved control valve system which is completely adequate to meet a greater variety of hydraulic applications, which gives improved performance, and which will operate efliciently over a long and useful life.

Further objects and advantages of the present invention will be apparent from the following description, reference being bad to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a sectional view of a preferred form of the present invention taken on line 11 of FIGURE 2.

FIGURE 2 is a sectional view of a preferred form of the present invention taken on line 2-2 of FIGURE 1.

FIGURE 3 is a diagrammatic view of a hydraulic power transmission system incorporating a preferred form of the present invention.

FIGURE 4 is a partial sectional view taken from FIG- URE 1 of a modified form of the present invention.

Referring now to FIGURE 1, there is shown a multiple valve bank comprising a plurality of directional

control valve sections

10, 12 and 14 held together by a plurality of bolts 16 in the usual manner. The valve section 10, which will be referred to as an inlet section, is comprised of a housing member 13 having a longitudinal valve bore 20 within which is shiftably mounted a directional control valve spool 22 for controlling a double acting motor and which has a stem 23 extending from the housing for manually selectively operating the same. The housing 18 of inlet section 10 is provided with three external connec tion ports shown in FIGURE 2, a pressure inlet or supply port 24 adapted for connection to a fluid pump, and utilization or

motor ports

26 and 28 adapted for connection of fluid in any operation of another fluid actuated to a double acting motor.

The valve section 12, which will be referred to as an cated by the to opposite ends of a double acting motor.

The valve section 14, which'will be referred to as an outlet section, is

comprised of a housing 40 having a longitudinal bore 42 within which is shiftably mounted a directional control valve spool type for controlling a single acting motor. It should also be understood that the intermediate section may be eliminated where two fluid. actuated devices are to be controlled.

The pressure delivery port 24 in the inlet section is connected by a flared cored recess 52 to a pressure delivery passage 54 which extends through housing 18 of said section and opens to a face thereof for registration with the opening of a pressure delivery passage 56 extending completely through the housing 50 of section 12, the opening on the opposite face of which is adapted to register with the opening of a pressure delivery passage 58 in housing 40 of outlet section 14 and having a closed end therein.

Each section is provided with a check valve bore indicated by the

numeral

60, 61 and 62 spaced apart from the directional valve bore in its associated housing, the inner ends of the

check valve bores

60, 61 and 62 being respectively intersected by the pressure delivery passage 54 in inlet section 10, pressure delivery passage 56 in intermediate section 12, and pressure delivery passage 58 in outlet section 14. For the purposes of convenience, the check valves which are adapted to be mounted in the said bores have not been shown, but it should be understood that the check valves when mounted in

bores

60, 61 and 62 open upwardly to connect the check valve bore 60 to a pressure port 64 of directional valve bore 20 (as shown in FIGURE 2), a pressure port 66 of directional valve bore 32, and a pressure port 68 of directional valve bore 42. The

check valve bores

60, 61 and 62 are adapted to be closed at one end thereby by plugs, all of which are indicated by the numerals 65.

Each directional valve bore is provided with utilization or

motor ports

70 and 72 on opposite sides of its associated pressure port and which independently lead to their respective external connection utilization or motor ports and are also provided with

return ports

74 and 76 spaced apart respectively from their utilization or

motor ports

70 and 72. Two

return passages

78 and 80 are formed in each housing to form two common return passages for the system which eventually respectively connect with cored return passages 79 and 81 in outlet section 14, the latter passages merging with a single return or tank passage 82 leading to the tank or return port 46. The

passages

78 and 80 in each housing are connected respectively to the valve

bore return ports

74 and 76 in said housings.

There is also provided a common by-pass or unloading passage which is formed as follows: each valve bore of the several housing members is provided with spaced apart by-

pass ports

84 and 86, the by-pass port 86 of housing 18 opening to a face of said housing to register with the opening of by-pass port 34 of housing 36 and the by-pass port 86 of housing 30 opening to a face thereof to register with the opening of the by-pass port 84 of housing 40. A by-pass passage 88 in the inlet section housing 18 connects the inlet port 24 thereof to the by-pass port 84 of value bore 20- in housing 18. As will hereinafter be explained, the by-pass port 86 of valve bore 42 in outlet section 14 is connected to the return passage 81 beyond valve member 44 and also to a by-pass port opening to a face of the housing 40 which can be opened or closed by a removable closure member.

Each directional control valve spool is provided with spaced apart lands for closing either the Dy-pass port 84 or port 86 and thus closing the common by-pass passage. Thus the valve 22 is provided with

lands

90 and 92 for respectively closing the by-

pass ports

84 and 86 of valve bore 20; the valve spool 34 is provided with

lands

91 and 93 for respectively closing the

bypass ports

84 and 86 associated with its valve bore 32; and the valve 44 is provided with lands 9'5 and 97 for closing the by-

pass ports

84 and 86 of its associated valve bore 42. Each directional control valve is biased to the neutral position shown by a spring 99 located between

retainers

101 and 103.

The

valve members

22 and 34 are also provided with spaced apart

lands

94 and 96 and the valve member 44 with a land 98. In the neutral position of the valves shown, the pressure ports 64 and 66 of

valves

22 and 34 are closed by the valve land 94 of each valve member from their respective utilization or

motor ports

70 and 72 while the pressure port 68 of valve 44 is closed from its single effective utilization or motor port 72 by the land 98. When either of the

valves

22 or 34 is shifted upwardly, the land 94 of each valve which had formerly closed the pressure ports 64 and 66 to the utilization or motor ports 72 of said valves will now open the pressure passage and port to the utilization or motor port 72, and the utilization or motor port 70 which had been closed both from the pressure port and return port will now be open to the return port 74 of said valve member.

When the

directional control valves

22 and 34 are shifted downwardly from the neutral position shown, the pres sure ports 64 and 66 of said valves are connected to the valve utilization or motor ports 70 while utilization or motor port 72 is connected to the return port 76 of the individual valve member.

When valve spool 44 of section 14 is shifted upwardly, pressure port 68 which had been closed to motor port 72 is now open thereto, and when the valve spool 44 is shifted downwardly from the position shown, motor port 72 which had been blocked from return port 76 is placed in communication with said port.

The construction and operation of the individual control valve members and of the system so far described is well known, that is, there is provided a multiple valve bank of the type having valve housings in side-by-side relation with common pressure delivery, return, and by-pass passages, and with individual utilization or motor ports for each housing. With all directional control valves in the neutral position, the common pressure delivery conduit is closed to communication with the motor or operating ports of the valve, and the by-pass passage, or unloading passage, which is interconnected to the pressure delivery pas sage ahead of the first valve member, remains open. Also, when any valve member is shifted from the neutral position, the valve member shifted closes the by-pass passage and opens the pressure delivery passage to a utilization or motor port of the shifted valve and, where a double acting valve is utilized, connects the remaining utilization or motor port to the common return passage.

Referring now to the improvements made in the control valve system described, means are provided for maintaining a regulated flow rate through the unloading or bypass passage when all valves are in the neutral position and for bypassing or shunting the remainder of the pressure fluid supply completely around the individual valve members by a separate passage connected to the return passage. For this purpose, the flared recess 52 in inlet section 10, and which is connected to the pressure delivery port 24, is not only connected to the common pressure delivery passage 54 but also communicates with a valve bore, indicated by the numeral 100, within. which is shiftably mounted a flow control valve 102 having mounted therein a pilot valve 104 for causing the flow control valve to also perform the function of a main relief valve.

The flow control valve 102 is of the substantially balanced type having two opposed operating surfaces indicated by the

numerals

106 and 108, the former of which is exposed to pressure in the inlet recess 52 ahead of a throttle 110 in the passage 88, the latter of which connects the inlet port 24 in the inlet section to the by-pass port 84 in valve section 10. The throttle 110 is formed in a throttling plug 111 threaded into the passage 88. The operating surface 108 is exposed to pressure beyond the throttle 110 by means of a passage 112 connected to passage 83 and by a passage 113 connected to passage 112 and leading to the lower portion of valve bore 100. interposed in the passage 112 is a restriction 114 adapted to cooperate in the relief valve function of flow control valve 102. For this purpose the pilot valve 104 is biased by a spring 116 to the position shown closing communi cation between a passage 120 and a passage 122 within the flow control valve, the passage 122 leading directly to an isolated exhaust passage 124'. The exhaust passage 124 extends through the housing 18 to meet with a similar isolated exhaust passage 124 extending through the housing 30 which meets with a similar exhaust passage 124 in housing member 44, the latter of which is directly connected to the return passage 81 in outlet section 14.

The flow control valve 102 is biased to the position shown by a spring 125 so that a land 126 of the valve blocks communication between the pressure delivery inlet recess 52 and the exhaust passage 124. The opposed operating surfaces 106 and 168 of the flow control valve are responsive to the differential in pressure across the throttle 110 in the passage 83, the pressure differential being established by the rating of spring 125. The flow control valve 102 operates in the well-known manner to maintain a constant pressure drop across the throttle 110 so that the flow through the by-pass passage will be at a uniform rate. Flow in excess of the regulated amount is bypassed across the land 126 of the flow control valve 102 to the exhaust passage 124, the latter of which shunts through the passage 124 all fluid in excess of the regulated rate completely around the directional control valve bores and valve members to the return passage in the last housing section beyond the last valve member. However, when any one or more of the directional control valve spools are shifted to close the common by-pass passage, a pressure differential no longer exists across the throttle 110 in passage 88. The pressure ahead of and beyond the throttle is equivalent to that existing in inlet recess 52, and the flow control valve 102 is maintained in a closed ineffective position by spring 125. The flow control valve 102 is thus incorporated in'the system in a manner to maintain a regulated flow rate only through the open by-pass passage. Fluid conducted to the pressure in to flow through the throttle 110 when being conducted by the inlet recess 52 to the common pressure delivery passage 54 when open so that the flow control valve is ineffective to maintain a regulated fiow rate through the common pressure delivery passage.

Whenever the pressure in the pressure delivery conduit reaches a maximum as determined by the rating of spring 116 of pilot valve 104, the pilot valve 104 shifts from a seat in the passage 120 to open passage 120 to passage 122 and thus to the exhaust passage 124. Because of restriction 114 in passage 112, the forces on the opposing operating

surfaces

106 and 108 of flow control valve 102 become completely unbalanced, and valve 102 shifts completely to exhaust excessive pressure fluid to the return passage 81 in the outlet section 14 through the common isolated exhaust passage 124.

Referring now to the outlet section 14, the housing 40 thereof is provided with an external connection by-pass port 128 which is connected by a passage 130 to the bypass port 86 of valve bore 42 and also to the return passage 81. As shown in FIGURE 1, a plate 132 is suitably fastened to the face of housing member 40 for closing the external connection port opening 128. The passage 130 is threaded, as indicated by the numeral 133, ahead of the connection of passage 130 to return passage 81 and beyond the connection of by-pass port 86 to passage 130, and a suitable plug may be inserted in the passage 130 as indicated by the numeral 134 in FIGURE 4. In applications Where it is desirable not only to operate a plurality of fluid motors utilizing the full displacement of the fluid pump but in addition operate another fluid 0perated device with a regulated flow, the plate be removed from the face of the housing 40 and 134 inserted in the threaded portion 133 of passage 130. In systems not requiring a regulated flow for the operation of a fluid operated device, the plate 132 is suitably fastened to the face external connection port serted in the passage 130.

Referring now to FIGURE 3, there is shown a hylet port 24 does not have draulic transmission system incorporating the improved control valve system. There is shown a fluid pump 136 which may be of the fixed displacement type driven by a prime mover, not shown, and which is connected at its inlet side by a conduit 138 to a tank 140 and connected at the outlet side thereof by a conduit 142 to the pressure inlet port 24 of section 10 of the control system. The utilization or

motor ports

26 and 28 of inlet section 10 are respectively connected by

conduits

144 and 146 to opposite ends of a double acting fluid motor 148 for driving a load device, not shown. The utilization or

motor ports

36 and 38 of intermediate section 12 are respectively connected by conduits 151) and 152 to opposite ends of another double acting fluid motor 154 for driving another load device, not shown. The utilization or motor port 48 of outlet section 14 is connected by a conduit 156 to a single acting fluid motor 158 for driving still another load device, not shown, while the tank or return port 46 of outlet section 14 is connected to the tank 140 by a conduit 160.

For the purpose of regulating the speed of a double acting fluid motor 162, a separate 4-way directional contrel valve 164 of conventional type may be provided, the pressure delivery port 166 of which ,is connected by a conduit 168 shown in dotted lines to theexternal connection by-pass port128 of outlet section 14. Motor or utilization ports 170 and 172 of the directional control valve 164 are respectively connected by

conduits

174 and 176 to opposite ends of the double acting fluid motor 162. As previously explained, when it is desired to regulate the speed of a motor such as motor 162, the plate 132 is removed from the by-pass port 128 in the outlet section 114, and a plug 134 (FIGURE 4) is threaded into the passage 130.

In the neutral position of the directional control valves shown in FIGURE 1, a portion of the displacement of the pump 136 conducted to pressure inlet port 24 is conducted through the common by-pass passage of the control valve system to the passage in the outlet section, and with plate 132 closing the by-pass port 128 and plug 134 removed from passage 130, is connected by the return passage 81 to passage 82 and thence to the tank port 46 from whence it is conducted to the tank by means of conduit 160. This displacement may be regulated so as to be one-haif, one-third, or any predetermined proportion of the displacement of the pump 136. The balance of the displacement from pump 136 is conducted through the bore 101) of the flow control valve 102 and thence through the common exhaust passage 124 of the several housing members to tank by means of exhaust passage 124 directly to the return passage 81 in the outlet section from whence it is directed to the tank 140. 1

directional control valve closing the by-pass. The flow control valve 102 becomes ineffective and is maintained in the closed positlon with the by-pass passage closed. When the speed 131). The displacement through the by-pass passage for controlling the speed of the motor 162 may be regulated by proper sizing of the throttle 110 in passage 38 and controlling the rating of spring 125 of the fiow control valve 102.

By use of the improved control valve system, it is possible to almost double the capacity of a control valve system of the same size not incorporating therein the controlled flow by-pass arrangement and to provide a controlled flow in any predetermined quantity for the operation of a fluid operated device. Although in the improved system the increased capacity does increase the pressure drop across the directional valves during the work cycle, this is a relatively short time in most mobile applications, and this is more than compensated for by the several advantages accruing. First and foremost of these advantages is the space saving of such improved system while another important asset is the cost saving, the savings in cost by the use of the flow control valve in the controlled flow by-pass part of the system as stated being much greater than a system without the controlled flow by-pass and having the same capacity.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A combined full flow and regulated flow directional control valve comprising: a housing having a valve bore, a plurality of passages connected to the bore including a pressure delivery passage, at least one utilization passage, a return passage, and a by-pass passage interconnected to the pressure delivery passage and to the return passage respectively ahead of and beyond the valve bore and extending to a face of the housing; a valve member in the bore normally closing the pressure delivery passage while leaving the by-pass passage open and selectively operable to connect the pressure delivery passage to the utilization passage while closing the by-pass passage; a throttle through which fluid flow in the by-pass passage must pass through; a flow control valve of the by-pass type in the housing responsive to the pressure differential across the throttle for maintaining a regulated flow rate only through the open by-pass passage; and two re movable closure members for the by-pass passage beyond the valve bore, one of which permits flow from the bypass passage to the return passage while blocking flow to the face of the housing, and the other of which blocks flow from the by-pass passage to the return passage.

2. A combined full flow and regulated flow direction-a1 control valve comprising: a housing having a valve bore, and a plurality of passages connected to the bore including a pressure delivery passage, at least one utilization passage, a return passage, and a bypass passage interconnected to the pressure delivery passage and to the return passage respectively ahead of and beyond the valve bore and extending to a face of the housing; a valve member in the bore normally closing the pressure delivery passage while leaving the by-pass passage open and selectively operable to connect the pressure delivery passage to the utilization passage while closing the by-pass passage; 2. throttle through which fluid flow in the by-pass passage must pass through; a flow control valve of the by-pass type in the housing responsive to the pressure differential across the throttle for maintaining a regulated flow rate only through the open by-pass passage; a separate passage connected to the flow control valve and to the return passage beyond the valve bore for shunting fluid in excess of the regulated amount around the valve member; and two removable closure members for the by-pass passage beyond the valve bore, one of which permits flow from the by-pass passage to the return passage While blocking flow to the face of the housing, and the other of which blocks flow from the bypass pass-age to the return passage.

3. A combined full flow and regulated flow multiple directional control valve system comprising: means forming a housing having a plurality of valve bores, and a plurality of passages including a pressure supply and a return passage connected to all the valve bores, at least one utilization passage connected to each v-alve bore, and a bypass passage connected to all the valve bores and to the pressure supply passage and to the return passage respectively ahead of and beyond the first and the last of said valve bores, said by-pass passage leading to and having an opening :on one face of the housing; a valve member in each bore shiftable from a neutral position for independently connecting the pressure sup-ply passage or the return passage to its associated utilization passage, said pressure delivery passage being closed and said by pass passage being open with all valves in a neutral position and said by-pass passage being closed when any valve member is shifted to connect the pressure supply passage to an associated utilization passage; a throttle through which fluid flow in said by-pass passage must pass; a flow control valve responsive to the pressure differential across the throttle for maintaining a regulated flow rate only through the open by-pass passage; a separate passage connected to the flow control valve and to the return passage beyond the last valve bore for shunting fluid in excess of the regulated by-pass rate around said valve members; and two removable closure means, one of which closes said by-pass passage at the face of said housing and the other of which closes communication between the by-pass passage and the return passage.

References Cited in the tile of this patent UNITED STATES PATENTS 2,359,802 Stephens Oct. 10, 1944 2,489,435 Robinson -a Nov. 29, 1949 2,503,870 Harrington Apr. 11, 1950 2,607,599 Kanuch Aug. 19, 1952 2,710,628 Hodgson June 14, 1955

Claims

1. A COMBINED FULL FLOW AND REGULATED FLOW DIRECTIONAL CONTROL VALVE COMPRISING: A HOUSING HAVING A VALVE BORE, A PLURALITY OF PASSAGES CONNECTED TO THE BORE INCLUDING A PRESSURE DELIVERY PASSAGE, AT LEAST ONE UTILIZATION PASSAGE, A RETURN PASSAGE, AND A BY-PASS PASSAGE INTERCONNECTED TO THE PRESSURE DELIVERY PASSAGE AND TO THE RETURN PASSAGE RESPECTIVELY AHEAD OF AND BEYOND THE VALVE BORE AND EXTENDING TO A FACE OF THE HOUSING; A VALVE MEMBER IN THE BORE NORMALLY CLOSING THE PRESSURE DELIVERY PASSAGE WHILE LEAVING THE BY-PASS PASSAGE OPEN AND SELECTIVELY OPERABLE TO CONNECT THE PRESSURE DELIVERY PASSAGE TO THE UTILIZATION PASSAGE WHILE CLOSING THE BY-PASS PASSAGE; A THROTTLE THROUGH WHICH FLUID FLOW IN THE BY-PASS PASSAGE MUST PASS THROUGH; A FLOW CONTROL VALVE OF THE BY-PASS