EP1556551B1 - Damping device - Google Patents

Abstract

What is disclosed is a a damping device, in particular for cable-supported structures such as, e.g., cable-stayed bridges, stadium roofs, guyed towers, comprising a differential cylinder, two hydraulic units, and an electric motor, wherein during damping the one hydraulic unit acts as a motor, and the second hydraulic unit acts as a pump, with surplus hydraulic energy being convertible into electric energy through the intermediary of the electric motor.

Description

The invention relates to a damping device, in particular for cable-supported structures such. As cable-stayed bridges, stadium roofs, guyed towers according to the preamble of claim 1.

The term "damping device" is understood to mean a hydraulic linear axis for a semiactive or active damping, in which essentially only control energy is entered.

The closest prior art JP-A-2001 241403 shows no damper device but a hydraulic control device for the bumpless movement of a hydraulic differential cylinder, comprising two hydraulic machines with electric motor, a hydraulic machine between the cylinder space and annulus of the hydraulic differential cylinder, the other between cylinder space and tank.

Cable-stayed bridges are nowadays regarded as the most economical solution for spans of around 150 m to 600 m. Recent developments show that spans of up to 1000 m are possible.

Although the material-saving, slim design of large cable-stayed bridges provides an architecturally appealing construction, the low internal damping leads to extremely susceptible to vibration structures. In particular, by wind excitation vibration amplitudes can be achieved, which require a blockage for traffic. The stress on the building parts (deck and ropes) is enormous and the associated costs are considerable.

The effect of known passive damper on the deck vibrations is not satisfactory. On the other hand, active damping devices, especially provided in the end abutments of the stay cables, cause a significant reduction of the vibration amplitude. However, the known designs have - in addition to the need for electrical point energy - a significant energy consumption.

Object of the present invention is to provide a damping device having an improved response and thus damping behavior with minimal energy requirements and reduced size of the actuator and allows the use of low-cost sensors.

This object is achieved by a damping device having the features according to the patent claim 1.

The damping device according to the invention comprises a differential cylinder, two hydraulic machines with adjustable pivoting angles, an electric motor associated with the hydraulic machines, a hydraulic accumulator connected to a cylinder chamber (34) of the differential cylinder (14) and a tank. A hydraulic machine is disposed in the pressure medium flow path between the tank and a piston rod side annulus, and the second hydraulic machine is positioned in the pressure medium flow path between the annulus and a cylinder space of the differential cylinder.

The speed with which a cylinder jacket (18) or piston (16) of the differential cylinder (14) moves, adjustable by an adjustment of the hydraulic machines (22, 24) or by a variable speed of the electric motor (26), so that a vibration damping Movement of the differential cylinder (14) is reached. Instead of the adjustable hydraulic or displacement machines and displacement machines can be used with a constant displacement. The required for the desired cylinder speed variable flow is then achieved by means of variable speed electric motor.

This arrangement according to the invention of the hydraulic machines, these are based against each other such that in the quasi-static state with appropriate design of hydraulic machines (depending on the selected pressure conditions) the remaining torque is zero (friction and change losses neglected) and thus the electric motor nahzu torque-free determines the speed , One of the hydraulic machines acts as a motor and drives the second hydraulic machine acting as a pump.

If, as a result of the vibrations, the damping device is subjected to dynamic forces, a higher pressure difference acts on the motor-operated hydraulic machine, whereas the hydraulic machine in pump operation must promote a smaller pressure difference. This energy surplus is - provided it exceeds the friction and other losses that result in the power flow - absorbed by the electric motor and can be fed into the electrical grid.

The electric motor is basically only necessary to set the damping device with low vibration excitation in operation, to specify the speed, or to make the excess power available as power or compensate for friction losses.

In a preferred embodiment, the differential cylinder is fixedly mounted via its piston on an end abutment of a cable-stayed bridge, wherein its cylinder jacket is displaceable in the longitudinal direction of the piston. A cable stay of the cable-stayed bridge is fastened to the cylinder jacket, so that by suitable control of the differential cylinder the vibrations acting in the structure or the dynamic forces acting thereon in the cable rope are damped by a longitudinal displacement of the cylinder jacket - according to the law of attenuation - thus avoiding uncontrolled stresses within the structure are.

The longitudinal displacement of the cylinder jacket as a result of external loads is made possible by adjusting the pivoting angle of the hydraulic machines. The swivel angles are adjustable so that the speed, with which moves the cylinder jacket, is proportional to the external loads. That is, large load requires large swivel angle, so that high pressure medium volume flows can be realized, while small loads cause small swivel angle, so that low pressure medium flow rates are possible.

In one embodiment, the cylinder jacket of the differential cylinder is mounted stationary and the piston of the differential cylinder guided axially displaceable.

In another embodiment, the adjustment of the pivoting angle or delivery volumes in response to a pressure signal of a arranged in the annulus or cylinder chamber pressure transducer.

In the static state (stroke = 0), a bias of the cable is set via the pressure prevailing in the annulus and cylinder chamber pressures. Ideally, the pressure in the cylinder chamber, which receives the static rope load, to the max. permissible system pressure. In the annulus of the differential cylinder about half system pressure is sought.

A further embodiment provides a pressure sensor in the cylinder chamber and / or in the region of the hydraulic accumulator for measuring and adapting the hydraulic accumulator pressure and the hydraulic accumulator charge to the respective static load.

In one embodiment, the hydraulic accumulator is integrated in the differential cylinder, so that a compact design is realized.

In another embodiment, the annular space of the differential cylinder relative to the environment and / or the cylinder chamber sealed by a gap seal, which is formed via an annular gap between the piston side and the cylinder shell side surfaces.

In a preferred embodiment, the annular gap opens to seal the annular space with respect to the external environment in a leak connection, wherein beyond the leakage connection at least one sealing element is provided for sealing the annular gap with respect to the atmosphere.

A particular advantage of such a gap seal is that the friction is reduced to a minimum and can be dispensed with cost-intensive and trouble-prone high-pressure seals.

Other advantageous embodiments of the invention are the subject of further subclaims.

• Figur 1 eine schematische Ansicht einer Schrägseilbrücke,
• Figur 2 einen Längsschnitt durch eine erfindungsgemäße Ausbildungsform mit einem externen Hydrospeicher,
• Figur 3 einen Längsschnitt durch eine erfindungsgemäße Ausbildungsform mit einem im Differentialzylinder integrierten Hydrospeicher und
• Figur 4 einen Längsschnitt durch einen Differentialzylinder mit Spaltdichtungen.

In the following, two preferred embodiments are explained in more detail with reference to schematic representations. Show it

• FIG. 1 shows a schematic view of a cable-stayed bridge,
• 2 shows a longitudinal section through an embodiment of the invention with an external hydraulic accumulator,
• 3 shows a longitudinal section through an embodiment of the invention with a built-in differential cylinder hydraulic accumulator and
• Figure 4 shows a longitudinal section through a differential cylinder with gap seals.

Figure 1 shows a cable-stayed bridge 2 with a roadway 4, which is supported by the main carrier 6. In order to reduce the loads acting on the main carriers 6, the roadway 4 is suspended from stay cables 8, which are supported by the main carriers 6. The stay cables 8 are mounted on damping devices 10 at the end abutments 12 of the roadway 4, so that cover vibrations can be damped.

FIG. 2 shows a longitudinal section through a preferred embodiment of a damping device 10. The damping device 10 has a differential cylinder 14, two hydraulic machines 22, 24, an electric motor 26, a hydraulic accumulator 42 and a tank 20.

The differential cylinder 14 has a stepped piston 16, which divides the space formed by the cylinder jacket 18 into two pressure chambers - a piston rod-side annular space 32 and a cylinder space 34.

The piston 16 of the differential cylinder 14 is fixedly mounted on the end abutment 12 via its radially stepped-back portion 28 - hereinafter referred to as piston rod, so that a lifting movement takes place via a longitudinal displacement of the cylinder jacket 18. Due to the two-sided hydraulic clamping of the piston 16, pressure medium is displaced from the one pressure chamber 32, 34 and nachgefördert in the other pressure chamber 34, 32, wherein missing or excess pressure fluid volume can be compensated by the tank 20 at each stroke movement.

On the cylinder jacket 18, the stay cable 8 engages, so that the bias of the cable 8 is predetermined over the pressure prevailing in the annular space 32 and cylinder space 34 pressures.

In kinematic reversal is, however, also conceivable to store the cylinder jacket 18 fixed to the end abutment 12 and to connect the piston rod 28 with the stay cable 8.

The first hydraulic machine 22 is arranged in a first working line 36 between the low-pressure side tank 20 and the high-pressure side annular space 32, wherein it is in communication with the electric motor 26. It has an adjustable delivery volume and can be used as pump or motor.

The second hydraulic machine 24 is arranged in a second working line 38 between the high pressure side annular space 32 and the high pressure side cylinder chamber 34, wherein the second working line 38 preferably opens into the first working line 36. According to the first hydraulic machine 22, the second hydraulic machine 24 also has an adjustable delivery volume, is also connected to the electric motor 26 and can be used as a pump or a motor.

Both hydraulic and displacement machines 22, 24 convey in two directions during vibration damping, with the first hydraulic machine 22 being high pressure resistant only on one side, i. the annular space side, and on the other side is applied low pressure, i. tank side, while the second hydraulic machine 24 on both sides high pressure resistant, i. must be on the annulus side and zyinderraumseitig, and can also reverse the direction of the pressure difference according to a 4-quadrant operation.

The delivery volumes of the hydraulic machines 22, 24 are adjustable in dependence on the signal of a load cell 40. The load cell 40 is arranged in the region of the connection cable stay 8 - cylinder jacket 18 and a control circuit of the hydraulic machines 22, 24 assigned. It detects the loads acting on the stay cable 8 and forwards the tensile stresses or tensile forces detected in the process to the control loop so that it depends on These external loads, the pivot angle of the hydraulic machines 22, 24 sets.

Another embodiment provides, instead of the cost-intensive force measurement, to use the pressure prevailing in the annular space 32 or cylinder space 34 as the feedback variable of the control loop. This can be done, for example, via a pressure transducer (not shown) arranged in the annular space 32 or cylinder chamber 34.

Furthermore, a hydraulic accumulator 42 is provided, which is connected by means of a third working line 44 with the second working line 38 and the cylinder chamber 34, so that the pressure in the cylinder chamber 34 is largely independent of the cylinder stroke and always prevails about the preset pressure.

The storage charge and the regulation of the accumulator pressure of the hydraulic accumulator 42 can advantageously be achieved by mutual dimming of the delivery volumes of the hydraulic machines 22, 24. For this purpose, a pressure transducer or pressure transducer is provided, which is preferably arranged in the hydraulic accumulator connection or in the working line 38 or in the cylinder chamber 34.

The electric motor 26 is in operative connection with the two hydraulic machines 22, 24, wherein it can be used both as a drive for the hydraulic machines 22, 24, as well as in the form of a generator by the hydraulic machines 22, 24 and thus acts as a brake. For example, via the driving of the hydraulic machines 22, 24, the preset pressures in the pressure chambers 32, 34 can be set and the hydraulic accumulator 42 can be charged. However, in hydraulic operation, the hydraulic energy generated by the first hydraulic machine 22 or the second hydraulic machine 24 can also be reduced by the circuit of the hydraulic system 22 during operation Electric motor 26 are converted as a generator into electrical energy.

The mode of action of this above-described arrangement according to the invention is explained in more detail below:

In the quasi-static state (stroke = 0), the damping device 10 is in equilibrium or in the rest position. In this case, a twice as high pressure as in the annular space 32 is preferably set in the cylinder space 34, so that about the first and second hydraulic machine 22, 24 are subjected to the same pressure difference. Since no vibration loads act on the stay cable 8, no force changes can be measured via the load cell 40. The swivel angle of the hydraulic machines 22, 24 is in its normal position, i. Swivel angle = 0th

In the vibration state (stroke ≠ 0) act as a result of the oscillations dynamic forces in the cable stay 8, whereby the balance is disturbed. It is important to differentiate between tensile and "compression" stress. Since only deviations from the static mean value are relevant for the damping control (the static loads are already compensated by the compressive prestressing), tensile stress in the following means that the tensile stress on the cylinder jacket 18 or the cylinder housing, which acts in the cable 8 - due to vibration - tends to increase an increase in pressure in the cylinder chamber 34 leads or hydraulic medium is displaced from there into the hydraulic accumulator 42, while this leads in the annular space 32 to a reduction of the pressure. On the other hand, the tensile stress acting in the cable 8 falls below the preset tension. That is, when pulling the cylinder jacket 18 moves according to Figure 1 to the left and "pressure" to the right.

The load cell 40 detects the tensile stresses occurring, depending on the signal of the load cell 40, the delivery volumes of the hydraulic machines 22, 24 are adjusted so that a stroke of the cylinder jacket 18 is allowed. Pressure medium is displaced via the respective working line 36, 38 from the decreasing pressure chamber 32, 34, wherein pressure medium in the increasing pressure chamber 34, 32 via the a hydraulic machine 22, 24 nachgefördert (pump function) is. In this case, the hydraulic machine 22, 24 connected as a pump is driven by the other hydraulic machine 24, 22 (motor).

At elevated tensile stress in the cable 8, the cylinder jacket 18 moves in Figure 1 to the left, so that the cylinder space 34 is reduced and the annulus 32 is increased. At the same time, the pressure in the annular space 32 drops below the preset pressure (for example <100 bar), while the pressure in the cylinder chamber 34 remains substantially unchanged (for example 200 bar) due to the compensating effect of the hydraulic accumulator 42. Thus, pressure medium flows from the cylinder chamber 34 via the second hydraulic machine 24 into the annular space 32, wherein the second hydraulic machine 24 is driven by the pressure medium flow and acts as a hydraulic motor. This then drives the first hydraulic machine 22 so that it is conveyed from the tank 20 into the annular space 32 by this pressure medium. Thus, the first hydraulic machine 22 acts as a pump. Since the pressure drop across the second hydraulic machine 24 is greater than the pressure drop across the first hydraulic machine 22, more power may be generated by the second hydraulic machine 24 (motor) than necessary to drive the first hydraulic machine 22, so that besides the first hydraulic machine 22 (pump) yet another customer could be operated. This further customer according to the invention, the electric motor 26, in this arrangement is operated as a generator and thus the excess hydraulic energy of the second hydraulic machine 24 converts into electrical energy or acts as a brake.

Thus, in tensile stress of the cable 8, the first hydraulic machine 22 acts as a pump, the second hydraulic machine 24 as a motor for the first hydraulic machine 22, and the electric motor 26 optionally as a generator, wherein a, the bridge deck vibration damping movement of the cylinder jacket 18, is realized.

Upon movement of the cable 8 to the right, the cylinder jacket 18 moves to the right, so that the cylinder space 34 is increased and the annular space 32 is reduced. The pressure in the annular space 32 rises (for example> 100 bar), while the pressure in the cylinder chamber 34 is kept constant via the hydraulic accumulator 42 (for example 200 bar). At the same time pressure medium flows from the annular space 32 via the first hydraulic machine 22 into the tank 20, so that it is driven by the pressure medium flow and acts as a hydraulic motor. This then drives the second hydraulic machine 24, so that it acts as a pump and promotes pressure medium from the annular space 32 in the cylinder chamber 34. In this case, the first hydraulic machine 22 (motor) generates more power than is required to drive the second hydraulic machine 24 (pump), so that a further pickup could be operated. This further consumer is according to the invention the electric motor 26, which is operated in this arrangement as a generator and thus converts the excess hydraulic energy of the first hydraulic machine 22 into electrical energy or acts as a brake.

Thus, at "compressive stress" of the cable 8, the first hydraulic machine 22 acts as a motor for the second Hydromachine 24, the second hydraulic machine 24 as a pump, and the electric motor 26 optionally as a generator, wherein a, the bridge deck vibration damping movement of the cylinder jacket 18, is realized.

As a result, according to the invention, a damping device 10 is provided which functions in the prestressed state substantially without external energy supply. All necessary energy to maintain or equalize the pressures can be covered in principle from the vibration energy according to the inventive design of the damping device 10.

In a preferred embodiment of the differential cylinder 14 (Figure 3), the hydraulic accumulator 42 is not disposed externally, but integrated in the differential cylinder 14 with its memory 64. The cylinder jacket 18 is extended in this embodiment and limits the memory 64, which is separated via a partition wall 46 from the cylinder chamber 34. To provide additional gas volume this is connected to external surge tanks 68. The partition wall 46 is acted on the cylinder space side with the pressure of pH in the cylinder chamber 34, so that they are axially displaced depending on the ratio between the gas pressure pG and the pressure pH and the pressure pH in the cylinder chamber 34 is kept substantially constant according to the laws of the state variables of the gas ,

Such an arrangement of the hydraulic accumulator 42 is particularly compact. Furthermore, the piping is simple, since no pressure medium line between the hydraulic accumulator 42 and the cylinder chamber 34 is necessary.

Figure 4 shows a preferred embodiment of a differential cylinder 14 with an inventive Sealing of an annular space 32 with respect to an external environment 62 and with respect to a cylinder space 34. The differential cylinder 14 has a multi-part piston 16 and a cylinder jacket 18. The differential cylinder 14 has at the free end portion 90 of its piston 16 a receptacle 72 for supporting the differential cylinder 14 at the end abutment 12 and the cylinder jacket 18 a receptacle 70 for attachment of a cable 8.

For measuring the stroke of the cylinder jacket 18, the differential cylinder 14 has a stroke measuring device 76, which is arranged on the front side of the cylinder jacket 18 and is in operative connection with the piston 16. In this case, the piston 16 has an annular element 66 which is in operative connection with a rod-shaped element 78 arranged on the cylinder jacket 18. The annular element 66 changes its relative position with respect to the longitudinal axis of the rod-shaped element 78 when strokes of the cylinder jacket 18, so that the stroke can be determined and a position control of the damping device 10 can be realized.

The annular space 32 (detail x) extends radially between a piston section 52 and an opposite cylinder jacket section 112 and is delimited axially by opposing end faces 92, 94 of a sliding sleeve 96 arranged on the cylinder jacket 18 and a spacer sleeve 100 arranged on the received end section 98 of the piston 16 , It is connected via radial bores 102, which open into an axial pressure channel, not shown, with a pressure port 104 for connecting the first working line 36 and the hydraulic machines 22, 24. In the region of the sliding sleeve 96, a leakage connection 60 is provided in the cylinder jacket 18.

The cylinder space 34 extends radially over the entire inner diameter of the cylinder jacket 18 and is axially limited by opposite end faces 86, 88 of the cylinder jacket 18 and the piston 16. It is connected via a pressure sleeve 106 arranged in the piston 16 to a pressure connection 108 for connecting the second working line 38 or the second hydraulic machine 24 and the hydraulic accumulator 42.

The sealing of the annular space 32 with respect to the outer environment 62 and the cylinder space 34 is realized via gap seals 48, 82 in the form of annular gaps 58, 84. In this case, the annular gap 58 for sealing the annular space 32 with respect to the outer environment 62 between the inner peripheral surface 54 of the sliding sleeve 96 and the respective outer peripheral portion 50 of the piston 16 is formed. The annular gap 58 opens into a leakage connection 60. The annular gap 84 for sealing the annular space 32 with respect to the cylinder space 34 is formed between the outer peripheral surface 52 of the spacer sleeve 100 and the respective opposite inner circumferential portion 112 of the cylinder jacket 18.

In order to achieve a sufficient tightness and a sufficiently large pressure reduction via the annular gaps 58, 84, these are radially correspondingly narrow and axially correspondingly long form.

Furthermore, radial sealing elements or wipers 80, 110 are provided on the other side of the leakage connection 60, which seal the annular gap 58 with respect to the external environment 62. In this case, only low-pressure seals 80, 110 are necessary due to the low pressure gradient between the pressure of the external environment 62 and the pressure of the pressure medium in the region of the leak port 60.

In addition to the absence of high-pressure seals for sealing the annular space 32 is particularly positive on the gap seals 48, 82 that the friction between opposing piston-side surfaces 50, 54 and cylinder jacket side surfaces 52, 56 is reduced, so that such a differential cylinder 14 has a better response than comparable Differential cylinder 14 having conventional seals.

Disclosed is a damping device, in particular for cable-supported structures such. B. cable-stayed bridges, stadium roofs, guyed towers with a differential cylinder, two hydraulic motors and an electric motor, in which at damping the hydraulic machine acts as a motor and the second hydraulic machine as a pump, wherein excess hydraulic energy via the electric motor into electrical energy is convertible.

LIST OF REFERENCE NUMBERS

2

Cable-stayed bridge

4

roadway

6

main carrier

8th

cable-stayed

10

damping device

12

Endwiderlager

14

differential cylinder

16

piston

18

cylinder surface

20

tank

22

first hydraulic machine

24

second hydraulic machine

26

electric motor

28

piston rod

32

annulus

34

cylinder space

36

first line of work

38

second working line

40

Load cell

42

hydraulic accumulator

44

third line of work

46

partition wall

48

gap seals

50

Outer peripheral portion

52

Outer circumferential surface

54

Inner peripheral portion

56

Inner peripheral portion

58

annular gap

60

leakage port

62

external environment

64

Storage

66

annular element

68

surge tank

70

admission

72

admission

74

pressure channel

76

Hubmesseinrichtung

78

rod-shaped element

80

Sealing element (low pressure seal)

82

gap seals

84

annular gap

86

face

88

face

90

free end section

92

face

94

face

96

sliding sleeve

98

recorded end portion

100

Stand Off

102

drilling

104

pressure connection

106

pressure sleeve

108

pressure connection

110

sealing element

112

Cylinder jacket section

Claims (13)

1. A damping device, in particular for cable-stayed bridges (2), comprising a differential cylinder (14), a tank (20), two hydraulic units (22, 24), a hydraulic accumulator (42) connected to a cylinder chamber (34) of the differential cylinder (14), and an electric motor (26) associated to the hydraulic units (22, 24), wherein a hydraulic unit (22) is arranged in the pressure medium flow path between the tank (20) and a piston rod-side ring chamber (32) and the second hydraulic unit (24) in the pressure medium flow path between the ring chamber (32) and the cylinder chamber (34), the moving velocity of a cylinder jacket (18) or piston (16) of the differential cylinder (14) being adjustable through an adjustment of the hydraulic units (22, 24) or a variable rotational speed of the electric motor (26) such that a vibration-damping movement of the differential cylinder is achieved..
2. The damping device in accordance with claim 1, characterized in that the hydraulic units (22, 24) each have a variable displacement volume.
3. The damping device in accordance with claim 1 or 2, characterized in that the electric motor (26) drives the hydraulic units (22, 24).
4. The damping device in accordance with claim 2, characterized in that a pressure transducer for measuring a pressure prevailing in the ring chamber (32) and/or in the cylinder chamber (34) is provided for adjusting the pivoting angles or displacement volumes of the hydraulic units (22, 24).
5. The damping device in accordance with claim 2, characterized in that in the cylinder chamber (34) and/or in the range of the hydraulic accumulator (42) a pressure transducer is provided for measuring an accumulator pressure and the accumulator charge of the hydraulic accumulator (42) and for adaptation to the static load.
6. The damping device in accordance with any one of the preceding claims, characterized in that the electric motor (26) is adapted to be driven through the intermediary of at least one of the hydraulic units (22, 24) and thus may be utilized as a generator.
7. The damping device in accordance with any one of the preceding claims, characterized in that in the quasi-static condition a pressure approximately twice as high as in the ring chamber (22) prevails in the cylinder chamber (24).
8. The damping device in accordance with any one of the preceding claims, characterized in that the piston (16) of the differential cylinder (14) is fixedly mounted, and the cylinder jacket (18) of the differential cylinder (14) is guided in an axially displaceable manner.
9. The damping device in accordance with any one of claims 1 to 7, characterized in that the cylinder jacket (18) of the differential cylinder (14) is fixedly mounted, and the piston (16) of the differential cylinder (14) is guided in an axially displaceable manner.
10. The damping device in accordance with claim 1, characterized in that the hydraulic accumulator (42) is integrated into the differential cylinder (14).
11. The damping device in accordance with any one of the preceding claims, characterized in that the ring chamber (32) is sealed against the external environment (62) and/or against the cylinder chamber (34) through the intermediary of a gap seal (48, 82).
12. The damping device in accordance with claim 11, characterized in that the gap seal (48, 82) is formed by an annular gap (58, 84) between piston-side surfaces (50, 54) and cylinder jacket-side surfaces (52, 56).
13. The damping device in accordance with claim 12, characterized in that beyond a leakage port (60), the annular gap (58) is sealed against the external environment (62) through the intermediary of at least one sealing member (80, 110).

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