GB1586429A - Hydraulic control units - Google Patents

Hydraulic control units Download PDF

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Publication number
GB1586429A
GB1586429A GB20202/78A GB2020278A GB1586429A GB 1586429 A GB1586429 A GB 1586429A GB 20202/78 A GB20202/78 A GB 20202/78A GB 2020278 A GB2020278 A GB 2020278A GB 1586429 A GB1586429 A GB 1586429A
Authority
GB
United Kingdom
Prior art keywords
outlet
flow controller
pressure source
controller
tank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB20202/78A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bosch Rexroth AG
Original Assignee
GL Rexroth GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GL Rexroth GmbH filed Critical GL Rexroth GmbH
Publication of GB1586429A publication Critical patent/GB1586429A/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3122—Special positions other than the pump port being connected to working ports or the working ports being connected to the return line
    • F15B2211/3127—Floating position connecting the working ports and the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40507—Flow control characterised by the type of flow control means or valve with constant throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40553—Flow control characterised by the type of flow control means or valve with pressure compensating valves
    • F15B2211/40569—Flow control characterised by the type of flow control means or valve with pressure compensating valves the pressure compensating valve arranged downstream of the flow control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41509—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50581—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups

Description

(54) IMPROVEMENTS IN OR RELATING TO HYDRAULIC CONTROL UNITS (71) We, G.L. REXROTH GmbH, a German body corporate of Postfach 340, Jahnstrasse, D-8770 Lohr/Main, Germany do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be described in and by the following statement: This invention relates to a hydraulic control unit for supplying working fluid from a pressure source to a plurality of consuming devices, hereinafter termed "consumers". The invention which may be applied to, for example, fork lift trucks, is concerned with such units having a threeway flow controller via which working fluid is supplied from the pressure source to at least one control slide valve.
In a known way the possibility is afforded, by the interposition of a 3-way flow controller between a pump connection and a series of consumers, of supplying to these consumers only a certain quantity of working liquid.
In the known case, there are provided, besides these consumers, further consumers which are connected independently of the 3-way flow controller directly to the pressure medium connection; the control liquid for the 3-way flow controller is conveyed via these control slide valves which are intended to be controlled independently of the 3-way flow controller. As soon as one of these control pistons is displaced out of the initial switching position into a switching position where the pressure medium source is connected to the consumer, the flow path for the control liquid which effect connection to the 3-way flow controller is interrupted and, consequently, the function of the 3-way flow controller is put out of action. For the consumers connected operatively to the 3-way flow controller merely a throttled, load-dependent control thereby takes place.
The problem of the invention consists of designing such a control unit that the consumers, generally requiring only a small quantity of working liquid and connected operatively to the 3-way flow controller, can be controlled in a load-independent way by the control slides in question even when a consumer independent of the 3-way flow controller is simultaneously connected by its control piston.
According to the invention there is provided a hydraulic control unit for supplying working fluid to a plurality of consumers comprising at least two control slide valves through which working fluid from a common pressure medium source inlet is supplied to respective consumers, at least one of said slides being connected to the pressure source via the controlled outlet of a three-way pressure controller, the other outlet of said controller for the remaining fluid being connected to a further control slide valve adapted to pass the remaining fluid to a tank outlet.
Preferably the control slides have three flow paths, one of which in the quiescent state serves to connect the pressure source inlet to the tank outlet, and one of said control slides and the three-way current controller are connected to the pressure source, and a plurality of control slides controlled by the flow controller are connected independently of one another to the outlet of the flow controller.
In a preferred embodiment, between the pressure source inlet and flow controller is connected a pressure relief valve discharging to the tank outlet.
In order that the invention may be readily understood a preferred embodiment thereof will now be described by way of example with reference to the accompanying drawing, which shows the switching diagram of a control unit according to the invention.
The dot-dash line 1 represents the control unit with the working line connections Al, B1, A2, B2, A3,B3, A4, B4, as well as the tank connection T and the pump connection P. The control unit has the control slides 2, 3, 4 and 5, which are all manually operated and have three flow paths a, b and c. In the initial switching position shown for the control slides the middle flow path b is opened, so that the pump connection P is connected to the tank connection T via the channel sections 6a, 6b, 6c, 6d and 6e and the working liquid flows directly from the pump connection P to the tank connection T without having to carry out any work. At the branching point 7 a channel 8 leads to the 3-way flow controller 9 via firmly adjusted throttle 10.In the closing direction the flow controller 9 is loaded via the control line 11 directly by the pump pressure and in the opening direction it is loaded by, apart from the force of the governing spring 12, the pressure behind the throttle 10 via the control line 13 with damping throttle 14.
The outlet 9a of the flow controller 9 is connected via the channel 15 with channel section 15a, 15b to the control slides 2, 3 and 4, namely, to their flow path c and the outlet 9b is connected via the channel 16 to the control slide 5, namely, to its flow paths b and c. The outlet 9a of the flow controller discharges a controlled flow of working liquid according to the throughflow crosssection of the throttle 10 and according to the pressure gradients in front of and behind the throttle 10 which are obtained from the spring characteristic of the control spring 12 of the 3-way flow controller, while the output 9b of the 3-way flow controller 9 discharges the remaining uncontrolled quantity of liquid.
From the flow paths a, c of each control slide channels al, bl, a2, a3, and a4, b4 lead to the relevant working line connections Al, B1, A2, A3, B3 and A4, B4. Connected to the working channels a3, b3, a4 and b4 are, in addition, relief valves 18, 19, 20 and 21 to safeguard the consumers in question.
Arranged in the working channel b2 is a pressure valve 17 which is bypassed in the direction of the consumer via the non-return valve 22 and which acts in the opposite direction as a supporting valve for the consumer.
There is connected simultaneously, via the branching point 7 and channel section 25, to the channel section 6a connected to the pump connection P, a relief valve 27 whose outlet channel 28 leads to the channel 29 connected to the tank connection T and, consequently, discharges in the direction of the tank as soon as the pump pressure exceeds the value set on this relief valve 27.
The control line 30 of the relief valve 27 is likewise connected via the branching point 31 to the channel section 6a.
If the control slide 5 is displaced out of the initial switching position k shown into the switching position 1, the flow paths a and b are interrupted and flow path c is closed with non-return valve 34. The flow of working liquid to the tank connection T is thereby interrupted and leads via the channel sections 6d2, 6dl to the closed flow path c and thence on via the channel bl to the working line connection B1. The consumer connection Al is shut off by a plug 33 and is consequently of no importance for the switching position of the control slide 5.If, for example, the control slide 3 is actuated simultaneously in this switching position l of the control piston 5, so that one of the consumer connections A3, B3 is connected to the channel section 15b, depending on the switching position of the conrol piston 3, the junction between the pump connection P and control slide 5 is simultaneously interrupted and, consequently, also the direct Junction of the working line connection B1 to the pump connection P. The consumer connection A3 or B3 in question receives the quantity of working liquid fixed on the 3-way flow controller 9 by the throttle 10 and governing spring 12, while the control slide 5 merely receives via the channel 16 the remaining quantity of working liquid from the 3-way flow controller.
The mode of action is the same when the control slides 2 or 4 are displaced out of the initial switching position shown into one of their working switching positions, while the working slide 5 is in the switching position 1.
In each of these working switching positions of the control slides 2, 3, 4 the middle flow path b is interrupted and, consequently, also the direct supply of working liquid from the pump connection P to the control slide 5 is forestalled, so that only the remaining quantity of working liquid from the 3-way flow controller is supplied to the said control slide via the channel 16.
Due to the fact that the 3-way flow controller 9 is arranged parallel to the control slides 2, 3 and 4 via the channel 8 branched by the channel 6a connected to the pump connection P and that the control slide 5 receives the remaining quantity of working liquid from the 3-way flow controller via a separate channel 16, the 3-way flow controller needs to be designed only for the relatively small quantity of working liquid to be controlled for the consumers assigned to the consumer connections A2, B2, A3, B3, A4, B4. Also, by the relief valve 27 connected via the channel section 25 to the 3-way flow controller the further advantage is achieved that the 3-way flow controller works as a 2-way flow controller when the consumer assigned to the consumer connection B1 has reached its end position and has no further requirement for working liquid.
The quantity of working liquid occurring in this case and intended for this consumer is supplied via the relief valve 27 and via the channels 28 and 29 directly to the tank connection T and thence on to the tank.
WHAT WE CLAIM IS: 1. A hydraulic control unit for supplying working fluid to a plurality of consumers comprising at least two control slide valves through which working fluid from a common pressure source inlet is supplied to respective consumers, at least one of said slides being connected to the pressure source via the controlled outlet of a threeway pressure controller, the other outlet of said controller for the remaining fluid being connected to a further control slide valve adapted to pass the remaining fluid to a tank outlet.
2. A hydraulic control unit according to Claim 1 in which the control slides valves have three flow paths one of which in the quiescent state serves to connect the pressure source inlet to the tank outlet and one of said control slide valves and the three-way current controller are connected directly to the pressure source and a plurality of control slide valves controlled by the flow controller are connected independently of one another to the outlet of the flow controller.
3. A hydraulic control unit according to Claim 1 or 2 in which between the pressure source inlet and flow controller is connected a pressure relief valve discharging to the tank outlet.
4. A hydraulic control unit substantially as hereinbefore described with reference to the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. supplied via the relief valve 27 and via the channels 28 and 29 directly to the tank connection T and thence on to the tank. WHAT WE CLAIM IS:
1. A hydraulic control unit for supplying working fluid to a plurality of consumers comprising at least two control slide valves through which working fluid from a common pressure source inlet is supplied to respective consumers, at least one of said slides being connected to the pressure source via the controlled outlet of a threeway pressure controller, the other outlet of said controller for the remaining fluid being connected to a further control slide valve adapted to pass the remaining fluid to a tank outlet.
2. A hydraulic control unit according to Claim 1 in which the control slides valves have three flow paths one of which in the quiescent state serves to connect the pressure source inlet to the tank outlet and one of said control slide valves and the three-way current controller are connected directly to the pressure source and a plurality of control slide valves controlled by the flow controller are connected independently of one another to the outlet of the flow controller.
3. A hydraulic control unit according to Claim 1 or 2 in which between the pressure source inlet and flow controller is connected a pressure relief valve discharging to the tank outlet.
4. A hydraulic control unit substantially as hereinbefore described with reference to the accompanying drawings.
GB20202/78A 1977-05-17 1978-05-17 Hydraulic control units Expired GB1586429A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2722238A DE2722238C2 (en) 1977-05-17 1977-05-17 Control block formed from several directional valves

Publications (1)

Publication Number Publication Date
GB1586429A true GB1586429A (en) 1981-03-18

Family

ID=6009190

Family Applications (1)

Application Number Title Priority Date Filing Date
GB20202/78A Expired GB1586429A (en) 1977-05-17 1978-05-17 Hydraulic control units

Country Status (4)

Country Link
DE (1) DE2722238C2 (en)
GB (1) GB1586429A (en)
IT (1) IT1094570B (en)
SE (1) SE7805564L (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2939327C2 (en) * 1979-09-28 1984-10-25 Mannesmann Rexroth GmbH, 8770 Lohr Control block for several hydraulic consumers that can be switched at the same time
DE3401775C2 (en) * 1984-01-19 1996-10-17 Linde Ag Hydrostatic device with an adjustable pump

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3465519A (en) * 1967-08-18 1969-09-09 Webster Electric Co Inc Hydraulic flow controlling apparatus

Also Published As

Publication number Publication date
IT1094570B (en) 1985-08-02
SE7805564L (en) 1978-11-18
DE2722238A1 (en) 1978-11-23
DE2722238C2 (en) 1982-09-23
IT7823148A0 (en) 1978-05-09

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee