GB2567994A - Hydraulic system and a spring-damper mechanism - Google Patents
Hydraulic system and a spring-damper mechanism Download PDFInfo
- Publication number
- GB2567994A GB2567994A GB1902975.0A GB201902975A GB2567994A GB 2567994 A GB2567994 A GB 2567994A GB 201902975 A GB201902975 A GB 201902975A GB 2567994 A GB2567994 A GB 2567994A
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- Prior art keywords
- accumulator
- piston
- chamber
- cylinder
- hydraulic
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Classifications
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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
- F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
- F15B1/02—Installations or systems with accumulators
- F15B1/021—Installations or systems with accumulators used for damping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
- F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
- F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
- F03B13/16—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
- F03B13/18—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore
- F03B13/1845—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom slides relative to the rem
- F03B13/1875—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom slides relative to the rem and the wom is the piston or the cylinder in a pump
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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
- F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
- F15B1/02—Installations or systems with accumulators
- F15B1/027—Installations or systems with accumulators having accumulator charging devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05B2260/00—Function
- F05B2260/40—Transmission of power
- F05B2260/406—Transmission of power through hydraulic systems
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05B2270/00—Control
- F05B2270/10—Purpose of the control system
- F05B2270/20—Purpose of the control system to optimise the performance of a machine
- F05B2270/202—Tuning to wave conditions
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
- Vehicle Body Suspensions (AREA)
Abstract
The invention relates to a hydraulic system with a hydraulic spring. Said spring is formed by a cylinder chamber of a hydraulic cylinder to which at least one piston accumulator is connected. At least one adjusting means for adjusting a pressure and/or a pressure medium quantity of the piston accumulator is provided. The pressure and/or the pressure medium quantity is adjusted independently of an energy withdrawal of a wave energy converter for the hydraulic system, energy withdrawal serving particularly for power generation.
Description
Description
Field of the invention
The invention relates to a hydraulic system according to the preamble of claim 1 and to a spring-damper mechanism, in particular a wave energy converter or a swell compensation device.
Background of the invention
Such a hydraulic system can for example be used in a spring-damper mechanism in the case of which it is for example a wave energy converter, an active swell compensation device or a spring-damper mechanism in automotive technology. A wave energy system (power take off (PTO)) with such a hydraulic system is represented respectively in DE 10 2007 056 400 A1 and in DE 10 2008 021 111 A1. The hydraulic system serves for power generation by way of an oscillating buoy. A double rod cylinder is provided here, whose piston is connected to the oscillating buoy and whose cylinder housing is fixed for example to a seabed. Cylinder chambers of the cylinder, which are separated by the piston, are connected to one another by a hydraulic pump active in both rotational directions. A generator is drivable by the hydraulic pump. Moreover, a spring-damper system is provided in order to ensure a stable vibration behaviour of the buoy.
Disclosure of the invention
In contrast to this, the object underlying the invention is to provide a robust and costeffective hydraulic system, for example for a wave energy converter and a springdamper mechanism by means of which a spring and/or damper characteristic can be adapted in a technically simple manner in order to operate for example the wave energy converter with the highest hydrodynamic efficiency.
This object is achieved by a hydraulic system according to the features of claim 1.
Advantageous further developments of the invention are the subject matter of the dependent claims.
According to the invention, a hydraulic system, in particular for wave energy converters, which particularly serve for power generation, are provided with a hydraulic cylinder. Said hydraulic cylinder is drivable by an oscillating natural force, in particular by a buoy, in particular by a completely submerged buoy or by a force. The hydraulic cylinder has, in this case, a cylinder chamber or spring chamber delimited by a piston. The cylinder chamber is preferably connected to an accumulator, in particular to a robust piston accumulator or robust cylinder accumulator. An adjusting means, in particular a hydraulic and/or pneumatic adjusting means, is advantageously provided for adjusting a pressure application of the accumulator. It is preferably adjusted independently of an energy withdrawal of the power that can be generated by the oscillating natural force or force.
This solution has the advantage that a separate “hydraulic spring” is formed with at least one cylinder chamber of the hydraulic cylinder together with the accumulator. A spring stiffness of the hydraulic cylinder accumulator system can be adjusted in a technically simple manner by adjusting the pressure application of the accumulator. Independently of the energy withdrawal by a further hydraulic cylinder or a further cylinder chamber in the hydraulic cylinder. The natural forces or forces can now be compensated in a technically simple manner with the spring mechanism or the hydraulic spring or the oil-hydraulic spring. For example, a resonance frequency of the wave energy converter can for example be adjusted with the hydraulic spring and therefore be adapted for example to a swell. The hydraulic system is designed technically very simply and cost-effectively.
A further cylinder chamber is preferably provided in the hydraulic cylinder for energy withdrawal. In this case, the hydraulic cylinder is for example designed as a multisurface cylinder. Alternatively or additionally, a further hydraulic cylinder can be provided for energy withdrawal. The further cylinder chamber and/or further hydraulic cylinder is/are preferably part of a hydrostatic drive rod. Said drive rod can then form a damping mechanism or damper, with kinetic energy of a pressure medium, which is for example formed by the oscillating buoy, being converted into electric energy. The drive rod is, in this case, preferably robustly and cost-efficiently designed, which leads to a cost-efficient solution in combination with the hydraulic spring. A hydraulic device is preferably provided to convert the kinetic energy of the pressure medium in the drive rod, said hydraulic device being capable of being connected to a generator by a drive shaft.
The accumulator, as already explained above, is preferably formed as a piston accumulator or cylinder accumulator or also as a bladder accumulator, which leads to a robust and safe hydraulic system. The piston accumulator has a piston, which separates a first accumulator chamber from a second accumulator chamber. The first accumulator chamber can then be easily connected to the cylinder chamber of the hydraulic cylinder. In order to adjust the spring stiffness of the hydraulic spring, provision can advantageously be made for a pressure and/or a pressure medium quantity to be adjusted on the side of the second accumulator chamber.
It is conceivable for one or a plurality of further accumulators, in particular piston accumulators or cylinder accumulators or bladder accumulators to be provided in parallel to the accumulator. The accumulator(s), in particular piston accumulators, can then also be connected with its first accumulator chamber to the cylinder chamber of the hydraulic cylinder and a pressure and/or a pressure medium quantity can be adjustable in the second accumulator chamber. The respective accumulator, in particular the piston accumulator, can be adjusted independently of the respective other accumulators, in particular piston accumulators.
Piston accumulators are preferably provided as the accumulators below, as already explained above, it being conceivable to alternatively provide a cylinder accumulator or bladder accumulator instead of a piston accumulator or instead of a part of the piston accumulator or instead of all piston accumulators.
A further second accumulator, in particular a piston accumulator or a cylinder accumulator, is preferably arranged in particular fluidically in series in relation to the first piston accumulator in addition to the (first) piston accumulator. The further second piston accumulator preferably also has a piston which separates a first accumulator chamber from a second accumulator chamber. The first accumulator chamber is then preferably fluidically connected to the second accumulator chamber of the first piston accumulator. A pressure and/or a pressure medium quantity can be hereby adjusted together in the connected accumulator chambers of the piston accumulators. Alternatively or additionally, it is conceivable for a pressure and/or a pressure medium quantity to be adjustable on the side of the second accumulator chamber of the second piston accumulator. A gas can be provided as the fluid for the second accumulator chamber of the second piston accumulator. It is conceivable to use oil for the other accumulator chambers of the piston accumulators. It is conceivable for the second accumulator chamber of the second piston accumulator to be connected to an accumulator, in particular to a gas accumulator. [SMJ1]
It can be provided that one or a plurality of additional accumulators are provided in addition to the further second accumulator fluidically in parallel to said second accumulator. In this case, it is conceivable for the further accumulators to also have a first and second accumulator chamber, the first accumulator chamber being capable of being connected to the second accumulator chamber of the first piston accumulator and the further second accumulator chambers each having a separate adjusting means for adjusting a pressure and/or a pressure medium quantity. Moreover, it is conceivable for the second accumulator chambers (gas sides) of the second piston accumulators to be connectable by regulating elements, for example valves or stop valves.
In a further configuration of the invention, the two piston accumulators, i.e. the first and second piston accumulators, form a piston accumulator pair. At least one further piston accumulator pair is preferably provided with a first and second piston accumulator. This accumulator pair can be arranged fluidically in parallel to the first piston accumulator pair. By providing a plurality of piston accumulator pairs, a spring stiffness can be more flexibly and precisely adjusted. A pressure and/or pressure medium quantity on the side of the connected accumulator chambers of the at least one further piston accumulator pair and/or in the second accumulator chamber of the second piston accumulator of the at least one further piston accumulator pair is/are also adjustable in particular independently of the other piston accumulator pair(s).
The second accumulator chamber of the piston accumulator or of the first piston accumulator or of the first piston accumulator of a respective piston accumulator pair is fluidically connectable to the cylinder chamber of the hydraulic cylinder by a hydraulic device of the adjusting means and/or by a valve of the adjusting means in order to adjust the pressure and/or the pressure medium quantity. A pressure and/or a pressure medium quantity can be hereby easily adjusted in the second accumulator chamber and in the cylinder chamber.
Alternatively or additionally, it can be provided that the second accumulator chamber of the piston accumulator or of the first piston accumulator or of the first piston accumulator of a respective piston accumulator pair is fluidically connectable to a low-pressure side by a hydraulic device of the adjusting means and/or by a valve of the adjusting means. It is therefore conceivable to feed the second accumulator chamber with pressure medium from the low-pressure side via the adjusting means or to release pressure medium from the second accumulator chamber to the lowpressure side. By way of such a configuration of the adjusting means, the spring stiffness can therefore be adjusted by modulating the pressure in the second accumulator chamber or in the intermediate volume.
Alternatively or additionally, it can be provided that the cylinder chamber of the hydraulic cylinder, which is connected to the piston accumulator(s), and/or that the first accumulator chamber of the first piston accumulator or of the first piston accumulators is fluidically connectable to a low-pressure side via a hydraulic device of the adjusting means and/or via a valve of the adjusting means. The hydraulic cylinder can therefore share with the first piston accumulator or the first piston accumulators an adjusting means for connecting to the low-pressure side.
A pressure medium quantity in the cylinder chamber of the hydraulic cylinder and in the second accumulator chamber of the piston accumulator or of the first piston accumulator or of the first piston accumulator of a respective piston accumulator pair can therefore in particular be adjusted in a technically simple manner with the hydraulic devices and/or valves of the adjusting means, a corresponding pressure being capable of being formed from the pressure medium quantity.
A linearity of the spring stiffness of the hydraulic spring or of the hydraulic cylinder can in particular be easily adjusted or approximated with the plurality of or numerous piston accumulator pairs. This in particular takes place by adjusting a pressure and/or a pressure medium quantity on the side of the second accumulator chamber of the second piston accumulator, i.e. in particular by adjusting a gas quantity and/or a gas pressure. On the side of the second accumulator chamber of the second piston accumulator of a respective piston accumulator pair, different pressure and/or pressure medium quantities are preferably provided in this case. The piston accumulator pairs are therefore differentiated by a different pressure or different pressure medium quantity in the second accumulator chamber of the second piston accumulator, the piston accumulator pairs otherwise being capable of being designed identically. Alternatively or additionally, it can be provided that in the intermediate volume, i.e. in the second accumulator chamber of the first piston accumulator and in the first accumulator chamber of the second piston accumulator of a respective piston accumulator pair a pressure medium quantity and/or pressure differing from the other piston accumulator pairs is provided.
It is conceivable for the accumulators to have different structural sizes. Therefore, different accumulator volumes can for example be provided in a parallel circuit.
If the hydraulic cylinder is configured as a multi-surface cylinder, the piston can thus, in addition to the cylinder chamber or spring chamber, delimit a further cylinder chamber for energy withdrawal. The cylinder chambers are preferably increased or decreased together when the piston moves. The piston of the multi-surface cylinder is preferably arranged displaceably in a cylinder housing. A roughly hollow-cylindrical cylinder rod can extend from the piston, said cylinder rod with its shell surface passing through a housing cover of the cylinder housing. The piston rod is sealed at its end outside of the cylinder housing. The cylinder rod, together with the cylinder base outside of the cylinder housing, delimits a cylinder chamber, which is preferably connected to the drive rod. The cylinder chamber or spring chamber is separated from the further cylinder chamber, which is used for energy withdrawal, by the hollow-cylindrical cylinder rod in the cylinder housing by its shell surface. Moreover, the piston can, on its side pointing away from the cylinder rod, delimit a further cylinder chamber, which is for example also usable as a spring chamber. A load, for example the buoy, is preferably connected to the cylinder housing, the cylinder rod for example being fixed to a seabed.
The spring stiffness can advantageously be adjusted with the hydraulic system. The spring stiffness can preferably be substantially linearly adjusted or approximated to a linearity with the system, i.e. a spring force varies roughly linearly via the stroke/travel. This can preferably be carried out by the second piston accumulators of the piston accumulator pairs, on the side of their second accumulator chamber, having different pressures and/or pressure medium quantities. Alternatively or additionally, it can be provided, in order to form a roughly linear spring stiffness, that the first piston accumulators of the piston accumulator pairs, on the side of their second accumulator chamber, have different pressures and/or pressure medium quantities. Therefore, it is advantageously provided, in order to form roughly a linear spring stiffness, that the second accumulator chambers of the second piston accumulators of the piston accumulator pairs have different gas fill quantities and/or that the intermediate volumes, i.e. the second accumulator chambers of the first piston accumulators of the piston accumulator pairs have different oil fill quantities from one another.
Advantageously, in the case of the hydraulic system, the spring stiffness, i.e. in particular an increase in the linear spring stiffness, can be adjustable. This preferably takes place by the pressures and/or pressure medium quantities, on the side of the second accumulator chamber of the second piston accumulators, being adjustable in the case of the piston accumulator pairs. Alternatively or additionally, the adjustment can take place by pressures and pressure medium quantities on the side of the second accumulator chamber of the first piston accumulators of a respective piston accumulator pair being adjusted. Moreover, alternatively or in addition to the adjustment of the spring stiffness, it can be provided to easily adjust a pressure and/or a pressure medium quantity in the cylinder chamber or spring chamber of the hydraulic cylinder. The piston accumulator pairs are in this case preferably adjusted together or an adjustment takes place for a respective piston accumulator pair with the same change, i.e. for example with the same quantity of pressure medium, which is fed or released. In this case, the piston accumulator pairs are preferably designed roughly identically for simplified adjustment.
It may be advantageously provided in the case of the hydraulic system to adjust a working point, in particular in addition to the spring stiffness by means of the adjusting means. For example, it may be provided that a spring force of the hydraulic cylinder is kept constant for different positions of the piston or that the spring force is adjustable for a determined position of the piston. The spring force of the hydraulic cylinder can therefore be kept substantially constant for different positions of the piston or the spring force of the hydraulic cylinder can be settable for a position of the piston of the hydraulic cylinder. This preferably follows a corresponding adjustment or setting of the pressure and/or pressure medium quantity on the side of the second accumulator chamber of the piston accumulator or of the first piston accumulator or of the first piston accumulator of the respective piston accumulator pair. Alternatively or additionally, this can take place by a corresponding adjustment or setting of the pressure and/or the pressure medium quantity on the side of the second accumulator chamber of the second piston accumulator or of the second piston accumulator of a respective piston accumulator pair.
It is conceivable for a bladder accumulator or membrane accumulator to be provided for example instead of the first and/or second very robust piston accumulator, with a bladder or a membrane serving as the separating element instead of a piston.
Advantageously, a wave energy converter with a hydraulic system is provided according to one or a plurality of the preceding aspects.
Short description of the drawings
Preferred exemplary embodiments of the inventions are explained in further detail below on the basis of schematic drawings. In which:
Fig. 1 shows in a simplified hydraulic circuit diagram a hydraulic system according to a first exemplary embodiment,
Fig. 2 to 4 each show by way of example a spring characteristic curve of the hydraulic system from Figure 1 and
Fig. 5 shows in a simplified hydraulic circuit diagram a hydraulic system according to a second exemplary embodiment.
According to Figure 1, a hydraulic system 1 is represented, which is used for a wave energy converter. Said wave energy converter has a hydraulic cylinder 2, which is formed as a multi-surface cylinder. The hydraulic cylinder 2 is, on the one hand, used as part of a “hydraulic spring” and, on the other hand, for power generation. The cylinder 2 has a cylinder housing 4, which is connected to an underwater buoy not represented. Together with the cylinder housing 4, this underwater buoy performs oscillating movements owing to a swell. A piston 6 is guided in a sliding manner in the cylinder housing 4. From said piston, a piston rod 8 extends in a direction away from a buoy not represented, said piston rod being connected for example to a seabed by fastening means 10. The piston rod 8 is designed roughly hollow-cylindrically and passes through a cylinder cover 12 of the cylinder housing 4. A projecting end of the piston rod 8 is closed. Inside the cylinder housing 4, the piston rod 8, together with the piston 6, delimits an outer circular cylinder chamber 14 or spring chamber and an inner circular cylinder chamber 16 separated therefrom. With its projecting part, the piston rod 8 delimits a further cylinder chamber 18. Moreover, the piston 6 with its side pointing away from the piston rod 8, delimits a cylinder chamber 20. The outer cylinder chamber 14 is used for the hydraulic spring. Moreover, it is conceivable for the upper cylinder chamber 20 to also be provided for a hydraulic spring. The cylinder chamber 16 and/or the cylinder chamber 18 is/are used for damping and/or for power regeneration. To this end, the cylinder chamber 16 and/or the cylinder chamber 18 is/are connectable inter alia to a hydraulic device 22, which is represented schematically in Figure 1 by a broken line.
The outer cylinder chamber 14 is connected to a first piston accumulator 26 by a flow path 24. This piston accumulator has a piston 28, which separates a first accumulator chamber 30 from a second accumulator chamber 32. The first accumulator chamber 30 is in this case connected to the outer cylinder chamber 14 by the flow path 24. The second accumulator chamber 32 is in turn connected to a second piston accumulator 36 by a flow path 34. This second piston accumulator also has a piston 38 which separates a first accumulator chamber 40 from a second accumulator chamber 42. The first accumulator chamber 40 is in this case fluidically connected to the second accumulator chamber 32 of the first piston accumulator 26. The second accumulator chamber 42 of the second piston accumulator 36 is connected to an accumulator 46 by a flow path 44. On the side of the second accumulator chamber 42, a gas is provided as the fluid. An oil is used as the fluid for the other accumulator chambers 40, 32, 30 with the further connected elements. The piston accumulators 26 and 36 form a piston accumulator pair 48 in the case of the hydraulic system 1.
Adjusting means are provided to adjust pressures and pressure medium quantities in the accumulator chambers 30, 32, 40, 42 and in the cylinder chamber 14. The flow path 24 is thus connectable to the flow path 34 by an adjusting means 50 in the form of a hydraulic device and/or in the form of a valve. The second accumulator chamber 32 of the first piston accumulator 26 and the first accumulator chamber 40 of the second piston accumulator 36 are therefore fluidically connectable to the cylinder chamber 14. Moreover, the cylinder chamber 14 can be connected to a low-pressure side 54 by the flow path 24 and a further adjusting means 52 in the form of a hydraulic device and/or in the form of a valve. Moreover, the flow path 34 is also connectable to the low-pressure side 54 by an adjusting means 56. The adjusting means 56 is designed in the form of a hydraulic device and/or in the form of a valve. An adjusting means can also be provided for the second accumulator chamber 42 of the second piston accumulator 36 in order to adjust a pressure and/or a pressure medium quantity of the gas, which is not shown in Figure 1.
In addition to the piston accumulator pair 48, one or a plurality of further piston accumulator pairs 58 can be provided which is indicated with a broken line in Figure 1. The at least one further piston accumulator pair 58 is installed into the hydraulic system 1 by separate adjusting means corresponding to the piston accumulator pair 48. An adjusting means is thus provided in order to connect a second accumulator chamber of a first piston accumulator to the cylinder chamber 14 and the lowpressure side 54. Moreover, the piston accumulator pair 58 can have a separate accumulator with gas and corresponding adjusting means. Two adjusting means are therefore respectively provided for the piston accumulator pair 58 or for a respective piston accumulator pair in order to connect them, on the one hand, to the cylinder chamber 14 and, on the other hand, to the low-pressure side 54.
The cylinder chamber 14 therefore acts together with the at least one piston accumulator pair 48 as a hydraulic spring.
The spring characteristic of the hydraulic system 1 is adjustable by the cylinder chamber 14 with the at least one connected piston accumulator pair 48 and the corresponding adjusting means 50, 52 and 56 independently of a damping characteristic. This is achieved by the cylinder chamber 14 being fluidically separated from the other cylinder chambers 16, 18 and 20. It would also be conceivable to use a separate hydraulic cylinder for the hydraulic spring, with one or a plurality of further hydraulic cylinders being provided for the power generation.
A spring characteristic curve for the hydraulic spring from Figure 1 is represented in Figure 2. This shows on its ordinate a spring force F and on its abscissa a spring path X. The hydraulic system from Figure 1 now allows the spring characteristic io curve to have a roughly linear course. A spring constant k is therefore roughly constant (k = dF/dx ~ constant). In order to achieve a linear course of the spring stiffness, it is provided that the at least two piston accumulator pairs 48 and 58, on their gas side, can each have a different pressure and/or a different pressure medium quantity. In addition, the at least two piston accumulator pairs 48 and 58 in their intermediate volume, i.e. for example according to piston accumulator pair 48 in the flow path 34, and the accumulator chambers 32 and 40, can have different pressures and/or pressure medium quantities.
According to Figure 3, it is represented in a spring characteristic curve of the hydraulic system 1 that the spring stiffness, in particular its increase, is adjustable (k = dF/dx = var). The spring stiffness is adjustable in this case by a pressure and/or a pressure medium quantity being adjusted in the accumulator chambers of the at least two piston accumulator pairs 48 and 58, which are connected to one another, such as for example the accumulator chambers 32 and 40. Moreover, the spring stiffness can be adjusted by a pressure and/or a pressure medium quantity being adjusted in the cylinder chamber 14. Alternatively or additionally, it can be provided, in order to adjust the spring stiffness, that a pressure or a pressure medium quantity of the gas side of a respective piston accumulator pair 48 and 58 is adjusted. The adjustment of the at least two piston accumulator pairs 48 and 58 preferably takes place with a roughly identical pressure medium quantity and/or a roughly identical pressure variation, in particular when the at least two piston accumulator pairs 48 and 58 are designed roughly identically.
According to Figure 4, it is shown that a working point can be influenced. Therefore, according to the marked line 60, the spring force can for example be kept constant for different displacements of the piston 6 from Figure 1. Or the spring force can, according to line 62, be adjusted for a determined displacement of the piston 6 from Figure 1.
According to Figure 5, a further embodiment of a hydraulic system 64 is represented. This hydraulic system 64 has a separate hydraulic cylinder 66 for the hydraulic spring. This separate hydraulic cylinder has a piston 68 from which a piston rod 70 extends, in the case of which the hydraulic cylinder 66 is a differential cylinder with a one-sided piston rod. A cylinder housing 72 of the hydraulic cylinder 66 is, in this case, connected to a buoy not represented and the hydraulic cylinder 66 is fixed by the piston rod 70. On the side of the piston rod 70, the piston 68 delimits a circular cylinder chamber 74. On its other side, the piston 68 delimits a cylinder chamber 76, which is connected to a hydraulic accumulator 78.
The cylinder chamber 74 is connected to a number of piston accumulator pairs 80 to 88 arranged fluidically in parallel. Each piston accumulator pair 80 to 88 respectively has a first piston accumulator 90 and a second piston accumulator 92. They are also designed as hydraulic cylinders with a piston and a piston rod projecting away from said piston on one side. A first accumulator chamber 94 of a respective first piston accumulator 90 is fluidically connected by a flow path 96 to the cylinder chamber 74 of the hydraulic cylinder 66. Moreover, the flow path 96 is connectable to a lowpressure side by an adjusting means 98. A second accumulator chamber 100 of the first piston accumulator 90 and a first accumulator chamber 102 of the second piston accumulator 92 of the first piston accumulator pair 80 are also fluidically connected directly to one another by a flow path 104. This applies correspondingly to the further piston accumulator pairs 82 to 88. The flow path 104 is connectable to the lowpressure side and to the flow path 96 by adjusting means 106 and 107, which is represented in Figure 5 for the sake of simplicity only for a flow path 104. Such an adjusting means 106 is provided for all piston accumulator pairs 80 to 88. Moreover, the second accumulator chambers of the piston accumulators 92 of the piston accumulator pairs are each connected to an accumulator 108, in particular to a gas accumulator.
According to Figure 5, the connectability of the second accumulator chambers 109 of two second piston accumulators 92 is represented with broken lines. The accumulator chambers 109 can be connected to one another by a regulating element 110. It is conceivable to provide a regulating element for connection between all second accumulator chambers of the second piston accumulators 92. The same applies to the embodiment from Figure 1, each two second accumulator chambers 42 also being connectable to one another by a regulating element.
The invention relates to a hydraulic system with a hydraulic spring. Said hydraulic spring is formed by a cylinder chamber of a hydraulic cylinder to which at least one piston accumulator is connected. At least one adjusting means for adjusting a pressure and/or a pressure medium quantity of the piston accumulator is provided. The pressure and/or the pressure medium quantity is adjusted independently of an energy withdrawal of a wave energy converter for the hydraulic system, energy withdrawal serving particularly for power generation.
List of reference numerals hydraulic system hydraulic cylinder cylinder housing piston piston rod fastening means cylinder cover cylinder chamber cylinder chamber cylinder chamber cylinder chamber hydraulic device flow path first piston accumulator piston first accumulator chamber second accumulator chamber flow path second piston accumulator piston first accumulator chamber second accumulator chamber flow path accumulator piston accumulator pair adjusting means adjusting means low-pressure side adjusting means piston accumulator pair line line hydraulic system hydraulic cylinder piston piston rod cylinder housing cylinder chamber cylinder chamber hydraulic accumulator to 88 piston accumulator pair first piston accumulator second piston accumulator first accumulator chamber flow path adjusting means
100 second accumulator chamber
102 first accumulator chamber
104 flow path
106 adjusting means
107 adjusting means
108 accumulator
109 accumulator chamber
110 regulating element
Claims (15)
1. Hydraulic system with a hydraulic cylinder (2), which is drivable by an oscillating force or natural force, wherein a cylinder chamber (14) delimited by a piston (6) of the hydraulic cylinder (4) is provided, characterised in that the cylinder chamber (14) is connected to an accumulator (26), wherein an adjusting means (50, 56) is provided for adjusting a pressure application of the accumulator (26), wherein the adjustment is independent of an energy withdrawal of power that can be generated by the oscillating force or natural force.
2. Hydraulic system according to claim 1, wherein a further cylinder chamber (16) is provided in the hydraulic cylinder (2) for the energy withdrawal and/or wherein a further hydraulic cylinder is provided for the energy withdrawal.
3. Hydraulic system according to claim 1 or 2, wherein the accumulator (26) has a piston (28) as the piston accumulator (26), which separates a first accumulator chamber (30) from a second accumulator chamber (32), wherein the first accumulator chamber (30) is connected to the cylinder chamber (14) of the hydraulic cylinder (2) and wherein a pressure and/or a pressure medium quantity is adjustable on the side of the first and/or on the side of the second accumulator chamber (30, 32).
4. Hydraulic system according to claim 3, wherein a further second piston accumulator (36) is provided with a piston (38), which separates a first accumulator chamber (40) from a second accumulator chamber (42), wherein the first accumulator chamber (40) is connected to the second accumulator chamber (32) of the first piston accumulator (26).
5. Hydraulic system according to claim 4, wherein a pressure or a pressure medium quantity is adjustable on the side of the second accumulator chamber (42) of the second piston accumulator (36).
6. Hydraulic system according to claim 5, wherein a gas is provided as the fluid for the second accumulator chamber (42) of the second piston accumulator (36) and/or wherein an oil is provided as the fluid for the first accumulator chamber (40) of the second piston accumulator (36) and for the two accumulator chambers (30, 32) of the second piston accumulator (26).
7. Hydraulic system according to any one of claims 4 to 6, wherein the two piston accumulators (26, 36) form a piston accumulator pair (48), wherein at least one further piston accumulator pair (58) is provided with a first and second piston accumulator that is arranged fluidically in parallel to the first piston accumulator pair (48).
8. Hydraulic system according to any one of claims 3 to 7, wherein the second accumulator chamber (32) of the piston accumulator (26) or of the first piston accumulator (26) or of the first piston accumulator (26) of a respective piston accumulator pair (48, 58) is fluidically connectable to the cylinder chamber (14) by a hydraulic device (50) of the adjusting means and/or by a valve (50) of the adjusting means and/or wherein the second accumulator chamber (32) of the piston accumulator (26) or of the first piston accumulator (26) or of the first piston accumulator (26) of a respective piston accumulator pair (48, 58) is fluidically connectable to the low-pressure side (54) by a hydraulic device (56) of the adjusting means and/or by a valve (56) of the adjusting means.
9. Hydraulic system according to claim 7 or 8, wherein the second accumulator chambers (109) of the piston accumulator pairs are connectable by a regulating element (110).
10. Hydraulic system according to any one of the preceding claims, wherein the cylinder chamber (14) of the hydraulic cylinder (2) is fluidically connectable to a/the low-pressure side (54) by a hydraulic device (52) of the adjusting means and/or by a valve (52) of the adjusting means.
11. Hydraulic system according to any one of claims 8 to 10, wherein the second piston accumulators (36) of at least two piston accumulator pairs (48, 58) are adjustable on the side of their second accumulator chamber (42) with different pressures and/or pressure medium quantities in order to provide a roughly linear spring stiffness of the hydraulic cylinder (2).
12. Hydraulic system according to any one of claims 4 to 11, wherein the first piston accumulators (26) of at least two piston accumulator pairs (48, 58) are adjustable on the side of their second accumulator chamber (32) with different pressures and/or different pressure medium quantities in order to provide a roughly linear spring stiffness of the hydraulic cylinder (2).
13. Hydraulic system according to any one of claims 3 to 12, wherein a spring stiffness of the hydraulic cylinder (2) is adjustable by the pressure and/or the pressure medium quantity on the side of the second accumulator chamber (32) of the piston accumulator (26) or of the first piston accumulator (26) or of the first piston
5 accumulator (26) of a respective piston accumulator pair (48, 58).
14. Hydraulic system according to any one of claims 3 to 12, wherein the spring stiffness of the hydraulic cylinder (2) is adjustable by the pressure and/or the pressure medium quantity on the side of the second accumulator chamber (42) of the second piston accumulator (36) or of a respective piston accumulator pair (48, io 58) and/or wherein a spring stiffness of the hydraulic cylinder (2) is adjustable by the pressure and/or the pressure medium quantity on the side of the cylinder chamber (14) of the hydraulic cylinder (2).
15. Spring-damper mechanism, in particular a wave energy converter or swell compensation device with a hydraulic system according to any one of the preceding
15 claims.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102016215062.6A DE102016215062A1 (en) | 2016-08-12 | 2016-08-12 | Hydraulic system and spring-damper mechanism |
| PCT/EP2017/067995 WO2018028942A1 (en) | 2016-08-12 | 2017-07-17 | Hydraulic system and a spring-damper mechanism |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201902975D0 GB201902975D0 (en) | 2019-04-17 |
| GB2567994A true GB2567994A (en) | 2019-05-01 |
Family
ID=59506238
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1902975.0A Withdrawn GB2567994A (en) | 2016-08-12 | 2017-07-17 | Hydraulic system and a spring-damper mechanism |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE102016215062A1 (en) |
| GB (1) | GB2567994A (en) |
| WO (1) | WO2018028942A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022200514A1 (en) * | 2021-03-24 | 2022-09-29 | Ocean Harvesting Technologies Ab | Power take-off device and wave energy converter unit comprising such power take-off device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108583800B (en) * | 2018-05-14 | 2019-10-29 | 山东大学 | A kind of integrated form active-passive composite heave compensator and its working method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006005497A1 (en) * | 2004-07-13 | 2006-01-19 | Bosch Rexroth Ag | Hydraulic control arrangement |
| DE102011111219A1 (en) * | 2011-08-20 | 2013-02-21 | Hydac System Gmbh | Energy conversion device for power plants and method for operating a device of this type |
| EP2725236A2 (en) * | 2012-10-29 | 2014-04-30 | Terex Cranes Germany GmbH | Telesopic unit with additional function |
| DE102014215313A1 (en) * | 2014-08-04 | 2016-02-04 | Robert Bosch Gmbh | Seegangskompensationseinrichtung |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102007056400A1 (en) | 2007-07-02 | 2009-01-08 | Robert Bosch Gmbh | Transducer and method for converting mechanical energy into electrical energy |
| DE102008021111A1 (en) | 2008-04-28 | 2009-10-29 | Robert Bosch Gmbh | Transducer and method for converting mechanical energy into electrical energy |
-
2016
- 2016-08-12 DE DE102016215062.6A patent/DE102016215062A1/en not_active Withdrawn
-
2017
- 2017-07-17 WO PCT/EP2017/067995 patent/WO2018028942A1/en active Application Filing
- 2017-07-17 GB GB1902975.0A patent/GB2567994A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006005497A1 (en) * | 2004-07-13 | 2006-01-19 | Bosch Rexroth Ag | Hydraulic control arrangement |
| DE102011111219A1 (en) * | 2011-08-20 | 2013-02-21 | Hydac System Gmbh | Energy conversion device for power plants and method for operating a device of this type |
| EP2725236A2 (en) * | 2012-10-29 | 2014-04-30 | Terex Cranes Germany GmbH | Telesopic unit with additional function |
| DE102014215313A1 (en) * | 2014-08-04 | 2016-02-04 | Robert Bosch Gmbh | Seegangskompensationseinrichtung |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022200514A1 (en) * | 2021-03-24 | 2022-09-29 | Ocean Harvesting Technologies Ab | Power take-off device and wave energy converter unit comprising such power take-off device |
Also Published As
| Publication number | Publication date |
|---|---|
| DE102016215062A1 (en) | 2018-02-15 |
| WO2018028942A1 (en) | 2018-02-15 |
| GB201902975D0 (en) | 2019-04-17 |
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