US20130323091A1 - Hydraulic System and Pressure Limiting Valve - Google Patents
Hydraulic System and Pressure Limiting Valve Download PDFInfo
- Publication number
- US20130323091A1 US20130323091A1 US13/906,848 US201313906848A US2013323091A1 US 20130323091 A1 US20130323091 A1 US 20130323091A1 US 201313906848 A US201313906848 A US 201313906848A US 2013323091 A1 US2013323091 A1 US 2013323091A1
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- United States
- Prior art keywords
- pressure
- limiting valve
- pressure limiting
- hydraulic
- valve
- 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.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/02—Stopping, starting, unloading or idling control
- F04B49/03—Stopping, starting, unloading or idling control by means of valves
- F04B49/035—Bypassing
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- 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
- F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
- F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
- F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
- F15B11/0423—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling pump output or bypass, other than to maintain constant speed
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- 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
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- 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
- F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
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- 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
- F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
- F15B2211/5157—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a return line
Definitions
- This invention relates to a hydraulic system with at least one consumer and at least one hydraulic pump, wherein a pressure limiting valve for limiting the maximum system pressure is connected with the at least one hydraulic pump.
- Hydraulic circuits and the hydraulic components thereof are designed for a definable maximum system pressure. Exceeding the maximum system pressure possibly leads to damages of the circuit and the components used. For this reason, pressure limiting valves are provided, which pass the delivery flow of the hydraulic pump through to the hydraulic tank, if the existing system pressure exceeds a maximum limit pressure value.
- a further pressure build-up or pressure control valve is used depending on the actuation of the individual hydraulic consumers within the hydraulic circuit.
- the required system pressure chiefly is determined by the delivery volume of the pump and the valve arrangement for actuating the hydraulic consumers.
- the system pressure can selectively be influenced via the used pressure build-up or pressure control valve, in order to reach and hold the desired system pressure level.
- the pressure control or build-up valve is arranged after the hydraulic pump and before the main control valves.
- the system pressure is looped through the downstream consumers and conveyed back to the hydraulic tank.
- it is required to arrange the pressure control or build-up valve not after the hydraulic pump, but after the consumer arrangement.
- the pressure build-up or control valves used mostly are designed as proportional gate-type 2/2-way valves.
- a disadvantage of the aforementioned known design is that there must always be used separate valves for the maximum pressure limitation, the pressure build-up and the bypass function. This increases the complexity of the switching construction as well as the necessary installation space and the manufacturing costs incurred.
- One object of the present invention is to indicate an improved hydraulic system and pressure limiting valve, which is able to overcome the disadvantages described above.
- a hydraulic system with at least one consumer and at least one hydraulic pump, wherein a pressure limiting valve for limiting the maximum system pressure is connected with the at least one hydraulic pump.
- the system pressure in particular is applied to the pressure limiting valve at the input side. When the applied system pressure exceeds a certain limit pressure level, the pressure limiting valve will switch through, in order to decrease the applied system pressure.
- the pressure limiting valve is pilot-controlled according to the invention.
- the pilot control serves for realizing a bypass function within the hydraulic system.
- the pressure limiting valve is switched for passage, in order to provide for a bypass or parallel shut-down path to the system pressure line.
- the system pressure is discharged directly from the hydraulic pump to a hydraulic tank.
- the pressure limiting valve is open in its neutral position and can be closed via the pilot control.
- a hydraulic system with at least one consumer and at least one hydraulic pump.
- the system comprises a pressure limiting valve connected with at least one hydraulic pump for limiting the maximum system pressure.
- the system pressure in particular is applied to the pressure limiting valve at the input side. When the applied system pressure exceeds a certain limit pressure level, the pressure limiting valve will switch through, in order to decrease the applied system pressure.
- the pressure limiting valve is pilot-controlled according to the invention. Via the pilot control, a pressure build-up or pressure control function additionally can be realized by a single valve beside the maximum pressure limitation. Expediently, it is provided that the pressure limiting valve is open in its neutral position and can at least partly be closed via the pilot control, in order to be able to adjust the input pressure or system pressure to a certain pressure level.
- the construction according to the invention provides for the combination of at least two valves or valve functions inside a single valve.
- a pressure control or pressure build-up valve additionally is realized via the pilot control of the pressure limiting valve.
- three valve functions can be performed by a single valve with a 4/3-way valve actuation of the hydraulic consumers in the hydraulic system. This allows an improved pressure build-up functionality as compared to the conventional pressure build-up valves.
- the integration of the various valve functions inside a valve permits a substantial reduction of the required number of hydraulic components. The production or manufacturing costs related therewith can be minimized. The same applies for the required installation space of the hydraulic circuit.
- the pressure limiting valve is designed as a proportional pressure limiting valve. This allows a proportional control of the system pressure to be limited between zero and the maximum system pressure.
- pilot control in principle is arbitrary. What is conceivable is an electric and/or electro-hydraulic design of the pilot control.
- pilot control also can be effected hydraulically or pneumatically.
- the embodiment of the pressure limiting valve also is to be chosen arbitrarily in principle.
- a cartridge or gate design represents a suitable construction.
- a possible configuration of the hydraulic system or the pressure limiting valve provides that the pilot control acts against a spring restoring force of the valve. When the pressure exerted by the pilot control exceeds the spring restoring force, the valve will switch.
- pilot control acts against the system pressure of the pressure limiting valve. It is particularly preferred when the pilot control acts against a spring restoring force and the system pressure. Hence, the maximum limit pressure can be adjusted via the force of the pilot control.
- a possible embodiment consists in that the pressure limiting valve is open in the neutral position.
- the open valve position is held by the spring force.
- the pilot control Upon actuation of the pilot control, the same acts against the restoring force of the spring.
- the variation of the pilot control provides for a partial or complete closure of the pressure limiting valve.
- the bypass function can be achieved for example by switching off the pilot control.
- the pilot control determines the target system pressure to be controlled as well as the maximum system pressure.
- the invention furthermore relates to a pressure limiting valve for limiting the system pressure inside a hydraulic system.
- the pressure limiting valve is pilot-controlled and the pilot control acts against a spring restoring force and/or the initially applied system pressure.
- the actuation or non-actuation of the pilot control leads to the switching of the pressure limiting valve.
- the desired system pressure level of a hydraulic system or the maximum system pressure can be adjusted via the control signal of the pilot control.
- pressure limiting valve is open in the neutral position, wherein the open valve position is held via the spring restoring force.
- a partial closure or a blocking position of the pressure limiting valve is achieved by varying the pilot control.
- the pilot control can be carried out hydraulically and/or pneumatically. Alternatively, the pilot control can also be carried out electrically and/or electro-hydraulically. As a suitable construction of the pressure limiting valve, a cartridge or gate design should be mentioned.
- pilot control provides for a proportional control of the initially applied system pressure to be limited.
- the construction as well as the properties and advantages of the pressure limiting valve according to the invention preferably correspond to those of the pressure limiting valve used inside the hydraulic system according to the invention, so that a repetitive description will be omitted at this point.
- FIG. 1 shows a schematic representation of a hydraulic system known from the prior art
- FIG. 2 shows a schematic representation of the hydraulic system according to the invention in a first design variant
- FIG. 3 shows a hydraulic circuit diagram of a partial region of the hydraulic system according to the invention as shown in FIG. 2 .
- FIG. 4 shows a further design variant of the hydraulic system according to the invention in a schematic representation.
- FIG. 1 shows a schematic representation of a hydraulic circuit according to the prior art.
- three hydraulic consumers 2 , 3 , 4 are fed, which are controlled jointly or each separately via at least one 4/3-way valve as main control valve.
- the system pressure inside line 5 is controlled via the delivery volume of the pump 1 as well as the switching position of the non-illustrated directional valves.
- a pressure limiting valve 6 is provided, which switches and enables the volume flow to the tank, as soon as the system pressure exceeds the maximum limit pressure.
- the system pressure inside line 5 in addition is controlled via a pressure build-up valve 7 .
- the valve 7 partly closes the flow to the tank.
- the hydraulic circuit as shown in FIG. 1 uses separate valves 6 , 7 for both functions, i.e. for the maximum pressure limitation and the pressure build-up. A possible valve arrangement for realizing a parallel shut-down path is not provided.
- FIG. 2 now shows a schematic representation of the hydraulic circuit of the invention according to a first advantageous design variant.
- the system likewise comprises a hydraulic pump 1 , which feeds a total of three hydraulic consumers 2 , 3 , 4 .
- the individual consumers are connected according to the 4/3-way technology.
- the pressure limiting valve 10 Beside its actual function of the maximum pressure limitation, the pressure limiting valve 10 according to the invention also has a bypass function as well as the function of a pressure build-up and pressure control valve.
- valve 10 is designed as proportional pressure limiting valve and allows a proportional control of the system pressure to be limited inside line 5 between zero and the maximum system pressure.
- the valve 10 hence combines a proportional control of the system pressure to be limited, the function of the pressure build-up and a bypass function for realizing a parallel shut-down path by delivering the pump volume flow directly to the hydraulic tank.
- FIG. 3 illustrates the concrete construction of the proportional pressure limiting valve 10 according to the invention. As shown in FIG. 3 , an individual consumer 2 is connected with the pump 1 via a 4/3-way valve 6 .
- the pressure limiting valve 10 remains in its neutral position due to the restoring force of the spring in the open position, so that hydraulic fluid can flow from the system pressure line 5 to the tank.
- the pressure limiting valve 10 is controlled directly via the input pressure.
- the system pressure of line 5 applied at the inlet acts in support of the restoring force of the spring.
- a pilot control which acts against the spring force or the system pressure.
- the illustrated drawing shows a hydraulic pilot control of the pressure limiting valve 10 via the hydraulic pressure p ctrl .
- an electric or electro-hydraulic pilot control also is conceivable just as well.
- the applied control pressure p ctrl determines the switching condition of the valve 10 .
- the control pressure p ctrl exceeds the restoring force of the spring and at least partly closes or completely blocks the valve 10 .
- the desired pressure level inside the system pressure line 5 now can be varied via the control pressure p ctrl , in that the valve 10 is partly opened.
- the function of a pressure build-up or pressure control valve thereby is satisfied.
- the control pressure level p ctrl determines the maximum limit pressure at which the pressure limiting valve 10 should open for safety reasons. For this purpose it is required that the system pressure as well as the restoring force of the spring together exceed the control pressure p ctrl and open the valve 10 .
- control pressure p ctrl simply is shut off during the operation.
- the spring restoring force opens the valve 10 , the parallel shut-down path is activated via the valve 10 to the tank.
- the construction of the pressure limiting valve 10 according to the invention is arbitrary in principle. Suitable design variants include a cartridge or gate design.
- a pressure build-up valve is provided downstream of the consumers.
- a possible construction of such hydraulic circuit can be taken from the schematic representation of FIG. 4 .
- the individual consumers 2 , 3 , 4 each are connected with the pump 1 via non-illustrated 6/3-way valves. It thereby is achieved that the system pressure line 5 is looped through the individual consumers 2 , 3 , 4 and for completion of the hydraulic circuit discharged into a tank.
- For the pressure build-up it is necessary to provide a suitable pressure build-up valve 20 downstream of the consumers 2 , 3 , 4 .
- the pressure limiting valve 10 likewise is connected directly to the hydraulic pump 1 .
- the function of the pressure build-up is not performed by the valve 10 , but the scope of functions is limited to the proportional control of the system pressure to be limited inside line 5 as well as the realization of a bypass function, in order to provide for a parallel shut-down path to the tank.
- the concrete construction of the hydraulic valve 10 corresponds to the one shown in FIG. 3 .
- the used pressure build-up valve 20 for example can be realized by a proportional gate-type 2/2-way valve.
Abstract
A hydraulic system has at least one consumer and at least one hydraulic pump. A pressure limiting valve for limiting the maximum system pressure is connected with the at least one hydraulic pump, and the pressure limiting valve is pilot-controlled for switching a bypass. The invention also concerns a pressure limiting valve for limiting the system pressure inside such a hydraulic system.
Description
- This application claims priority to
German Patent Application 10 2012 011 062.6, filed Jun. 4, 2012, the entire disclosure of which is incorporated herein by reference. - This invention relates to a hydraulic system with at least one consumer and at least one hydraulic pump, wherein a pressure limiting valve for limiting the maximum system pressure is connected with the at least one hydraulic pump.
- Hydraulic circuits and the hydraulic components thereof are designed for a definable maximum system pressure. Exceeding the maximum system pressure possibly leads to damages of the circuit and the components used. For this reason, pressure limiting valves are provided, which pass the delivery flow of the hydraulic pump through to the hydraulic tank, if the existing system pressure exceeds a maximum limit pressure value.
- As an additional safety measure it often is requested that a bypass shutdown is realized via a further valve. By actuating the provided valve, the delivery flow of the hydraulic pump is recirculated directly to the hydraulic tank, the system pressure then will drop.
- In addition, depending on the actuation of the individual hydraulic consumers within the hydraulic circuit, a further pressure build-up or pressure control valve is used. The required system pressure chiefly is determined by the delivery volume of the pump and the valve arrangement for actuating the hydraulic consumers. In addition, the system pressure can selectively be influenced via the used pressure build-up or pressure control valve, in order to reach and hold the desired system pressure level.
- When the consumers are actuated via a 4/3-way technology, i.e. via individual 4/3-way valves (main control valves), the pressure control or build-up valve is arranged after the hydraulic pump and before the main control valves.
- In a 6/3-way technology, the system pressure is looped through the downstream consumers and conveyed back to the hydraulic tank. In this case, it is required to arrange the pressure control or build-up valve not after the hydraulic pump, but after the consumer arrangement.
- The pressure build-up or control valves used mostly are designed as proportional gate-
type 2/2-way valves. - A disadvantage of the aforementioned known design, however, is that there must always be used separate valves for the maximum pressure limitation, the pressure build-up and the bypass function. This increases the complexity of the switching construction as well as the necessary installation space and the manufacturing costs incurred.
- One object of the present invention is to indicate an improved hydraulic system and pressure limiting valve, which is able to overcome the disadvantages described above.
- This object is solved by a hydraulic system according to the features included in the independent claims below. Further advantageous embodiments of the hydraulic system form the subject-matter of the dependent claims.
- According to the invention, there is proposed a hydraulic system with at least one consumer and at least one hydraulic pump, wherein a pressure limiting valve for limiting the maximum system pressure is connected with the at least one hydraulic pump. The system pressure in particular is applied to the pressure limiting valve at the input side. When the applied system pressure exceeds a certain limit pressure level, the pressure limiting valve will switch through, in order to decrease the applied system pressure.
- Furthermore, the pressure limiting valve is pilot-controlled according to the invention. The pilot control serves for realizing a bypass function within the hydraulic system. In particular, by actuation or non-actuation of the pilot control, the pressure limiting valve is switched for passage, in order to provide for a bypass or parallel shut-down path to the system pressure line. In this case, the system pressure is discharged directly from the hydraulic pump to a hydraulic tank. Expediently, it is provided that the pressure limiting valve is open in its neutral position and can be closed via the pilot control.
- According to an alternative aspect of the invention, there is proposed a hydraulic system with at least one consumer and at least one hydraulic pump. The system comprises a pressure limiting valve connected with at least one hydraulic pump for limiting the maximum system pressure. The system pressure in particular is applied to the pressure limiting valve at the input side. When the applied system pressure exceeds a certain limit pressure level, the pressure limiting valve will switch through, in order to decrease the applied system pressure.
- Furthermore, the pressure limiting valve is pilot-controlled according to the invention. Via the pilot control, a pressure build-up or pressure control function additionally can be realized by a single valve beside the maximum pressure limitation. Expediently, it is provided that the pressure limiting valve is open in its neutral position and can at least partly be closed via the pilot control, in order to be able to adjust the input pressure or system pressure to a certain pressure level. The construction according to the invention provides for the combination of at least two valves or valve functions inside a single valve.
- It is particularly advantageous when beside the bypass function the function of a pressure control or pressure build-up valve additionally is realized via the pilot control of the pressure limiting valve. In this case, three valve functions can be performed by a single valve with a 4/3-way valve actuation of the hydraulic consumers in the hydraulic system. This allows an improved pressure build-up functionality as compared to the conventional pressure build-up valves. In addition, the integration of the various valve functions inside a valve permits a substantial reduction of the required number of hydraulic components. The production or manufacturing costs related therewith can be minimized. The same applies for the required installation space of the hydraulic circuit.
- In a particularly advantageous embodiment, the pressure limiting valve is designed as a proportional pressure limiting valve. This allows a proportional control of the system pressure to be limited between zero and the maximum system pressure.
- The realization of the pilot control in principle is arbitrary. What is conceivable is an electric and/or electro-hydraulic design of the pilot control.
- Alternatively, the pilot control also can be effected hydraulically or pneumatically.
- The embodiment of the pressure limiting valve also is to be chosen arbitrarily in principle. A cartridge or gate design represents a suitable construction.
- A possible configuration of the hydraulic system or the pressure limiting valve provides that the pilot control acts against a spring restoring force of the valve. When the pressure exerted by the pilot control exceeds the spring restoring force, the valve will switch.
- It is likewise conceivable that the pilot control acts against the system pressure of the pressure limiting valve. It is particularly preferred when the pilot control acts against a spring restoring force and the system pressure. Hence, the maximum limit pressure can be adjusted via the force of the pilot control.
- A possible embodiment consists in that the pressure limiting valve is open in the neutral position. The open valve position is held by the spring force. Upon actuation of the pilot control, the same acts against the restoring force of the spring. The variation of the pilot control provides for a partial or complete closure of the pressure limiting valve. The bypass function can be achieved for example by switching off the pilot control. In addition, the pilot control determines the target system pressure to be controlled as well as the maximum system pressure.
- The invention furthermore relates to a pressure limiting valve for limiting the system pressure inside a hydraulic system. According to the invention it is provided that the pressure limiting valve is pilot-controlled and the pilot control acts against a spring restoring force and/or the initially applied system pressure. The actuation or non-actuation of the pilot control leads to the switching of the pressure limiting valve. In addition, the desired system pressure level of a hydraulic system or the maximum system pressure can be adjusted via the control signal of the pilot control.
- It is particularly advantageous when the pressure limiting valve is open in the neutral position, wherein the open valve position is held via the spring restoring force. A partial closure or a blocking position of the pressure limiting valve is achieved by varying the pilot control.
- The pilot control can be carried out hydraulically and/or pneumatically. Alternatively, the pilot control can also be carried out electrically and/or electro-hydraulically. As a suitable construction of the pressure limiting valve, a cartridge or gate design should be mentioned.
- It is particularly advantageous if the pilot control provides for a proportional control of the initially applied system pressure to be limited.
- The construction as well as the properties and advantages of the pressure limiting valve according to the invention preferably correspond to those of the pressure limiting valve used inside the hydraulic system according to the invention, so that a repetitive description will be omitted at this point.
- Further advantages and properties of the invention will be explained in detail with reference to the attached drawings, in which:
-
FIG. 1 shows a schematic representation of a hydraulic system known from the prior art, -
FIG. 2 shows a schematic representation of the hydraulic system according to the invention in a first design variant, -
FIG. 3 shows a hydraulic circuit diagram of a partial region of the hydraulic system according to the invention as shown inFIG. 2 , and -
FIG. 4 shows a further design variant of the hydraulic system according to the invention in a schematic representation. -
FIG. 1 shows a schematic representation of a hydraulic circuit according to the prior art. Via thehydraulic pump 1 threehydraulic consumers line 5 is controlled via the delivery volume of thepump 1 as well as the switching position of the non-illustrated directional valves. For safety reasons, a pressure limiting valve 6 is provided, which switches and enables the volume flow to the tank, as soon as the system pressure exceeds the maximum limit pressure. - The system pressure inside
line 5 in addition is controlled via a pressure build-up valve 7. To achieve the desired target pressure insideline 5, the valve 7 partly closes the flow to the tank. The hydraulic circuit as shown inFIG. 1 uses separate valves 6, 7 for both functions, i.e. for the maximum pressure limitation and the pressure build-up. A possible valve arrangement for realizing a parallel shut-down path is not provided. -
FIG. 2 now shows a schematic representation of the hydraulic circuit of the invention according to a first advantageous design variant. The system likewise comprises ahydraulic pump 1, which feeds a total of threehydraulic consumers pressure limiting valve 10 according to the invention also has a bypass function as well as the function of a pressure build-up and pressure control valve. - In detail, the
valve 10 is designed as proportional pressure limiting valve and allows a proportional control of the system pressure to be limited insideline 5 between zero and the maximum system pressure. Thevalve 10 hence combines a proportional control of the system pressure to be limited, the function of the pressure build-up and a bypass function for realizing a parallel shut-down path by delivering the pump volume flow directly to the hydraulic tank. - The hydraulic circuit diagram of
FIG. 3 illustrates the concrete construction of the proportionalpressure limiting valve 10 according to the invention. As shown inFIG. 3 , anindividual consumer 2 is connected with thepump 1 via a 4/3-way valve 6. - The
pressure limiting valve 10 remains in its neutral position due to the restoring force of the spring in the open position, so that hydraulic fluid can flow from thesystem pressure line 5 to the tank. Thepressure limiting valve 10 is controlled directly via the input pressure. The system pressure ofline 5 applied at the inlet acts in support of the restoring force of the spring. - According to the invention, there is furthermore provided a pilot control which acts against the spring force or the system pressure.
- The illustrated drawing shows a hydraulic pilot control of the
pressure limiting valve 10 via the hydraulic pressure pctrl. However, an electric or electro-hydraulic pilot control also is conceivable just as well. The applied control pressure pctrl determines the switching condition of thevalve 10. - For the pressure build-up inside
line 5 it is necessary that the control pressure pctrl exceeds the restoring force of the spring and at least partly closes or completely blocks thevalve 10. Subsequently, the desired pressure level inside thesystem pressure line 5 now can be varied via the control pressure pctrl, in that thevalve 10 is partly opened. The function of a pressure build-up or pressure control valve thereby is satisfied. Apart from this, the control pressure level pctrl determines the maximum limit pressure at which thepressure limiting valve 10 should open for safety reasons. For this purpose it is required that the system pressure as well as the restoring force of the spring together exceed the control pressure pctrl and open thevalve 10. - For realizing the bypass function of the valve, the control pressure pctrl simply is shut off during the operation. The spring restoring force opens the
valve 10, the parallel shut-down path is activated via thevalve 10 to the tank. - The construction of the
pressure limiting valve 10 according to the invention is arbitrary in principle. Suitable design variants include a cartridge or gate design. - If one or
more consumers FIG. 4 . Theindividual consumers pump 1 via non-illustrated 6/3-way valves. It thereby is achieved that thesystem pressure line 5 is looped through theindividual consumers valve 20 downstream of theconsumers - According to the first design variant, the
pressure limiting valve 10 according to the invention likewise is connected directly to thehydraulic pump 1. As compared to the first variant, however, the function of the pressure build-up is not performed by thevalve 10, but the scope of functions is limited to the proportional control of the system pressure to be limited insideline 5 as well as the realization of a bypass function, in order to provide for a parallel shut-down path to the tank. The concrete construction of thehydraulic valve 10 corresponds to the one shown inFIG. 3 . - The used pressure build-up
valve 20 for example can be realized by a proportional gate-type 2/2-way valve. - The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
Claims (16)
1. A hydraulic system comprising:
at least one consumer,
at least one hydraulic pump, and
a pressure limiting valve for limiting a maximum system pressure connected with the at least one hydraulic pump,
wherein the pressure limiting valve is pilot-controlled for switching a bypass.
2. The hydraulic system according to claim 1 , wherein pilot control of the pressure limiting valve provides for a proportional control of the system pressure to be limited.
3. The hydraulic system according to claim 1 , wherein pilot control of the pressure limiting valve is effected electrically, electro-hydraulically, or electrically and electro-hydraulically.
4. The hydraulic system according to claim 1 , wherein pilot control of the pressure limiting valve is effected hydraulically, pneumatically, or hydraulically and pneumatically.
5. The hydraulic system according to claim 1 , wherein the pressure limiting valve has a cartridge design, a gate design, or a cartridge and gate design.
6. The hydraulic system according to claim 1 , wherein pilot control of the pressure limiting valve acts against at least one of a spring restoring force and a system pressure.
7. The hydraulic system according to claim 1 , wherein the pressure limiting valve does not allow an increase of the system pressure without actuation.
8. A hydraulic system comprising:
at least one consumer,
at least one hydraulic pump, and
a pressure limiting valve for limiting a maximum system pressure connected with the at least one hydraulic pump,
wherein the pressure limiting valve is pilot-controlled in order to additionally carry out a pressure build-up or pressure control function as well as limiting the maximum system pressure.
9. The hydraulic system according to claim 8 , wherein the pressure limiting valve is pilot-controlled for switching a bypass.
10. The hydraulic system according to claim 8 , wherein pilot control of the pressure limiting valve provides for a proportional control of the system pressure to be limited.
11. The hydraulic system according to claim 8 , wherein pilot control of the pressure limiting valve is effected electrically, electro-hydraulically, or electrically and electro-hydraulically.
12. The hydraulic system according to claim 8 , wherein pilot control of the pressure limiting valve is effected hydraulically, pneumatically, or hydraulically and pneumatically.
13. The hydraulic system according to claim 8 , wherein the pressure limiting valve has a cartridge design, a gate design, or a cartridge and gate design.
14. The hydraulic system according to claim 8 , wherein pilot control of the pressure limiting valve acts against at least one of a spring restoring force and a system pressure.
15. The hydraulic system according to claim 8 , wherein the pressure limiting valve does not allow an increase of the system pressure without actuation.
16. A pressure limiting valve for limiting the system pressure inside a hydraulic system, wherein the pressure limiting valve is pilot-controlled and pilot control of the pressure limiting valve acts against at least one of a spring restoring force and an input pressure.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102012011062A DE102012011062A1 (en) | 2012-06-04 | 2012-06-04 | Hydraulic system and pressure relief valve |
DE102012011062.6 | 2012-06-04 |
Publications (1)
Publication Number | Publication Date |
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US20130323091A1 true US20130323091A1 (en) | 2013-12-05 |
Family
ID=48444013
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/906,848 Abandoned US20130323091A1 (en) | 2012-06-04 | 2013-05-31 | Hydraulic System and Pressure Limiting Valve |
Country Status (5)
Country | Link |
---|---|
US (1) | US20130323091A1 (en) |
EP (1) | EP2672124A2 (en) |
JP (1) | JP2013249957A (en) |
CN (1) | CN103452960A (en) |
DE (1) | DE102012011062A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10626986B2 (en) * | 2016-10-31 | 2020-04-21 | Hydraforce, Inc. | Hydraulic motor drive system for controlling high inertial load rotary components |
US20210148352A1 (en) * | 2017-07-13 | 2021-05-20 | Nel Hydrogen A/S | A method of controlling the hydraulic fluid pressure of a diaphragm compressor |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102018203568A1 (en) * | 2018-03-09 | 2019-09-26 | Zf Friedrichshafen Ag | Automatic transmission with a hydraulic system |
DE102019000212A1 (en) * | 2019-01-12 | 2020-07-16 | Hydac Fluidtechnik Gmbh | Circuit arrangement |
CN111946878B (en) * | 2020-08-14 | 2021-06-15 | 哲弗智能系统(上海)有限公司 | Sub-control valve, fire extinguishing device and fire extinguishing system |
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US4209039A (en) * | 1978-04-10 | 1980-06-24 | Tadeusz Budzich | Load responsive control valve |
US4290448A (en) * | 1978-11-15 | 1981-09-22 | Tadeusz Budzich | Load responsive control valve |
USRE30828E (en) * | 1975-11-26 | 1981-12-22 | Load responsive valve with constant leakage device | |
US4327763A (en) * | 1980-01-11 | 1982-05-04 | Tadeusz Budzich | Dual control input flow control valve |
US4330009A (en) * | 1979-06-18 | 1982-05-18 | Tadeusz Budzich | Exhaust pressurization of load responsive system |
US4330991A (en) * | 1980-01-02 | 1982-05-25 | Tadeusz Budzich | Load responsive system controls |
US4488474A (en) * | 1983-01-17 | 1984-12-18 | Caterpillar Tractor Co. | Fully compensated fluid control valve |
US6752600B2 (en) * | 2002-04-19 | 2004-06-22 | Wayne Engineering Corporation | Fluid system |
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US7418885B2 (en) * | 2004-05-15 | 2008-09-02 | Luk Lamellen Und Kupplungsbau Beteiligungs Kg | Device for driving a plurality of hydraulic shift cylinders and hydraulic supply system for a twin-clutch transmission |
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US8925439B2 (en) * | 2011-01-13 | 2015-01-06 | Husco International, Inc. | Valve control valve circuit for operating a single acting hydraulic cylinder |
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DE2904474A1 (en) * | 1979-02-07 | 1980-08-28 | Bosch Gmbh Robert | Flow control for variable pump - has pump positioner control valve actuated by throttle differential via pilot pressure varying valve |
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CN2851674Y (en) * | 2005-11-11 | 2006-12-27 | 肖玉龙 | Proportional pilot hydraulic control system for small-sized radial wheel type excavator |
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-
2012
- 2012-06-04 DE DE102012011062A patent/DE102012011062A1/en not_active Ceased
-
2013
- 2013-05-13 EP EP13002504.2A patent/EP2672124A2/en not_active Withdrawn
- 2013-05-31 JP JP2013115827A patent/JP2013249957A/en active Pending
- 2013-05-31 US US13/906,848 patent/US20130323091A1/en not_active Abandoned
- 2013-06-03 CN CN2013102181257A patent/CN103452960A/en active Pending
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USRE30828E (en) * | 1975-11-26 | 1981-12-22 | Load responsive valve with constant leakage device | |
US4164119A (en) * | 1978-03-27 | 1979-08-14 | J. I. Case Company | Hydraulic pump unloading system |
US4209039A (en) * | 1978-04-10 | 1980-06-24 | Tadeusz Budzich | Load responsive control valve |
US4290448A (en) * | 1978-11-15 | 1981-09-22 | Tadeusz Budzich | Load responsive control valve |
US4330009A (en) * | 1979-06-18 | 1982-05-18 | Tadeusz Budzich | Exhaust pressurization of load responsive system |
US4330991A (en) * | 1980-01-02 | 1982-05-25 | Tadeusz Budzich | Load responsive system controls |
US4327763A (en) * | 1980-01-11 | 1982-05-04 | Tadeusz Budzich | Dual control input flow control valve |
US4488474A (en) * | 1983-01-17 | 1984-12-18 | Caterpillar Tractor Co. | Fully compensated fluid control valve |
US6752600B2 (en) * | 2002-04-19 | 2004-06-22 | Wayne Engineering Corporation | Fluid system |
US6857444B2 (en) * | 2002-10-25 | 2005-02-22 | Briggs & Stratton Power Products Group, Llc | Flow-actuated trapped-pressure unloader valve |
US7418885B2 (en) * | 2004-05-15 | 2008-09-02 | Luk Lamellen Und Kupplungsbau Beteiligungs Kg | Device for driving a plurality of hydraulic shift cylinders and hydraulic supply system for a twin-clutch transmission |
US7513109B2 (en) * | 2005-09-02 | 2009-04-07 | Kobelco Construction Machinery Co., Ltd. | Hydraulic controller for working machine |
US8925439B2 (en) * | 2011-01-13 | 2015-01-06 | Husco International, Inc. | Valve control valve circuit for operating a single acting hydraulic cylinder |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10626986B2 (en) * | 2016-10-31 | 2020-04-21 | Hydraforce, Inc. | Hydraulic motor drive system for controlling high inertial load rotary components |
US20210148352A1 (en) * | 2017-07-13 | 2021-05-20 | Nel Hydrogen A/S | A method of controlling the hydraulic fluid pressure of a diaphragm compressor |
US11815081B2 (en) * | 2017-07-13 | 2023-11-14 | Nel Hydrogen A/S | Method of controlling the hydraulic fluid pressure of a diaphragm compressor |
Also Published As
Publication number | Publication date |
---|---|
EP2672124A2 (en) | 2013-12-11 |
JP2013249957A (en) | 2013-12-12 |
DE102012011062A1 (en) | 2013-12-05 |
CN103452960A (en) | 2013-12-18 |
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Legal Events
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AS | Assignment |
Owner name: LIEBHERR-FRANCE SAS, FRANCE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HELBLING, FRANK;MUELLER, CHRISTOPH;HAPPEL, SIMON;REEL/FRAME:031251/0894 Effective date: 20130710 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |