DE102013212560A1 - Cylinder and cylinder arrangement with such a cylinder - Google Patents

Abstract

Disclosed is a three-chamber cylinder with a cylinder housing and a piston displaceable therein, which has a piston rod. With the piston, a first of a second cylinder chamber is separated. If pressure medium is charged into the first or second cylinder chamber and discharge pressure medium from the second or first cylinder chamber, the piston or the cylinder housing is displaced in the axial direction. It is provided a spring which is supported on the displaceable component, ie on the piston or the cylinder housing, and is displaceable together with this. The spring in turn acts on a piston unit with a spring force. The piston unit defines together with the cylinder housing a pressure chamber, via which it can be acted upon to bias the spring with pressure medium.

Description

The invention is based on a cylinder according to the preamble of claim 1 and a cylinder assembly with such a cylinder.

Such cylinders or actuators are used, for example, in the power plant area for actuating Kolbeneinheitn or control valves for gas and steam turbines. Furthermore, it is conceivable to use such cylinders in metallurgy, water treatment, petrochemistry or chemistry. A deployment onshore or offshore is also conceivable. Since these piston unit in the said power plant area must close safely and very quickly (<0.2 sec.) In case of failure, a control function of the cylinder of a quick-closing function is superimposed. This is realized by a mechanical spring, which can safely close the piston unit in case of error.

For example, cylinders are known from the prior art, which are designed as a synchronous cylinder, and in which piston unit, the piston unit is acted upon by a spring with a spring force in the shooting direction. When controlling the piston unit, the spring is constantly stretched or relaxed. It must therefore be overcome to actuate the piston unit with the actuating force in addition to the spring force.

From the EP 1 283 370 A2 a cylinder arrangement is known as a pitch drive for a wind turbine. Here, a first piston is arranged in an axially movable cylinder housing, which is connected via a piston rod with a second arranged in a fixed cylinder housing piston. The first piston limits cylinder chambers, via which a position of the movable cylinder housing can be regulated. Depending on the position of the cylinder housing, a pitch of rotor blades of the wind turbine is set. The second piston then defines a cylinder chamber, via which the second piston can be acted upon with pressure medium in order to be displaced axially. With an axial displacement of the second piston, the first piston is additionally displaced together with the cylinder housing. The second piston then serves to return the rotor blades to a safe flag position.

In contrast, the invention has for its object to provide a cylinder and a cylinder assembly with such a cylinder which is simple and has a low energy consumption.

This object is achieved with regard to the cylinder having the features of claim 1 and with regard to the cylinder arrangement having the features of claim 8.

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

Disclosed is a cylinder with a cylinder housing and a piston arranged therein. From this, a piston rod extends. The piston separates in the cylinder housing a first of a second cylinder chamber. For displacing the piston or the cylinder housing, the piston or the cylinder housing can be acted upon with pressure medium via the cylinder chambers. Via a spring, a piston unit is acted upon by a spring force, wherein the spring is supported on the displaceable piston or on the displaceable cylinder housing. The piston unit then limited together with the displaceable piston or the displaceable cylinder housing a pressure chamber, via which it can be acted upon to bias the spring with pressure medium.

This solution has the advantage that the piston unit is not moved relative to the spring when actuated via the displaceable piston or the displaceable cylinder housing, since the spring is moved together with the piston unit and the displaceable piston or the displaceable cylinder housing. For this reason, the spring force is not overcome in a regular movement of the piston unit, resulting in low energy consumption and low heat losses compared to the prior art, which is why a risk of overheating of the cylinder decreases. To relax the spring pressure medium is then released from the pressure chamber, with which the piston unit is then displaced into its closed position. The pressure chamber and the spring then form a quick-closing function of the cylinder. During normal control of the piston unit, it is then firmly clamped by the spring force and a pressure force of the pressure medium in the pressure chamber on the displaceable piston or on the displaceable cylinder housing. Another advantage is that when controlling the piston unit sealing means for sealing the pressure chamber is not loaded by a movement of the piston unit relative to the spring and / or relative to the displaceable piston or the displaceable cylinder housing. As a result, frictional forces are largely avoided. The cylinder thus has a reduced frictional force during a control movement of the piston unit. Another advantage of the cylinder is that it has an extremely small number of components, which reduces manufacturing costs and a susceptibility to errors. The cylinder is thus relatively simple and inexpensive.

Since the spring used as a quick-release spring is not moved along with each control movement of the piston unit, this advantageously does not have to be designed durable. A guide of the spring is also extremely simple, since it is moved together with the piston unit and the piston to be displaced or the cylinder housing to be moved.

In a preferred embodiment, the piston unit has a second piston with a second piston rod, with which the piston unit is firmly connected. The second piston can then limit the pressure chamber in the displaceable cylinder housing or in the displaceable piston or in the piston rod of the displaceable piston. The pressure chamber is then penetrated by the second piston rod.

Advantageously, the first piston rod protrudes on one end face of the cylinder housing and the second piston rod on the other end face of the cylinder housing.

The second piston can limit the pressure chamber with its end face pointing away from the first piston and with its other end face a cylinder chamber in the displaceable piston or the displaceable cylinder housing. The cylinder chamber bounded by the other end face can then be pressure-relieved. It is preferably arranged in the axial direction between the pressure chamber and the first and second cylinder chamber.

In a further preferred embodiment of the invention, the piston unit has a second cylinder housing. With this the piston unit is firmly connected. The second cylinder housing then limits the pressure chamber with the displaceable first cylinder housing or the displaceable piston. In this case, the second cylinder housing preferably surrounds the cylinder housing or the piston.

For limiting the pressure chamber, the displaceable cylinder housing preferably has a piston, which is designed, for example, as a radial collar which delimits the pressure chamber in the second cylinder housing of the piston unit.

Advantageously, the spring is supported on a radial collar of the displaceable piston or of the displaceable cylinder housing.

A cylinder arrangement according to the invention with a cylinder according to the invention provides that pressure medium can be discharged from the pressure chamber via a quick-acting valve, in particular to a hydraulic accumulator. If the pressure medium discharged, the spring can relax and move the piston unit, for example, in a closed position. This then takes place relative to the displaceable piston or the displaceable cylinder housing.

In a further embodiment of the cylinder arrangement, the latter has a hydraulic machine which is fluidically connected to the first cylinder chamber via a first pressure line and to the second cylinder chamber via a second pressure line. The pressure chamber is then advantageously connected via a valve with the first pressure line and can be filled via this. Via a further valve, the pressure chamber can then also be connected to the second pressure line and thus be filled via this.

Extremely simple in terms of apparatus, the valves can be designed as check valves which open in a pressure medium flow direction to the pressure chamber.

In order to limit the pressure in the pressure chamber, this is connected to a pressure relief valve which opens the pressure medium connection from a certain pressure to the hydraulic accumulator.

With a pressure fluid flow path between the quick-acting valve and the hydraulic accumulator, the first and / or the second pressure line can be fluidly connected in each case via a valve.

The valves are simply check valves, which preferably close in the direction of pressure fluid flow toward the pressure medium flow path.

The hydraulic machine is preferably variable in speed via an electric actuator, for example an electric motor, and can be driven in both directions of rotation. The cylinder chambers are then simply charged by driving the hydraulic machine via the electric motor with pressure medium or it is discharged from these pressure medium.

The first piston is preferably connected to a further piston rod, whereby the first and second cylinder chamber are respectively penetrated by a piston rod, whereby a synchronous cylinder is formed, which preferably leads to a volume compensation.

In a further embodiment of the cylinder arrangement, the cylinder chamber acting in the opening direction on the piston unit can be connected to a pressure limiting valve, whereby, for example, a pressure impact acting in the opening direction on the piston unit can be damped.

In the following, preferred embodiments of the invention are explained in more detail with reference to drawings. Show it:

1 1 is a schematic representation of a cylinder arrangement according to the invention with a cylinder according to the invention according to a first exemplary embodiment,

2 in a schematic representation of the cylinder according to a second embodiment,

3 in a schematic representation of the cylinder according to a third embodiment and

4 in a schematic representation of the cylinder according to a fourth embodiment.

According to 1 has the cylinder arrangement 1 a cylinder 2 , This has an axially displaceable cylinder housing 4 , which is designed for example as a cylinder tube in which a first piston 6 is arranged. This has a first piston rod 8th up, coming from a floor 10 of the cylinder housing 4 protrudes. The piston rod 8th is about a fastening device 12 fixable. The piston 6 separates a first cylinder chamber 14 from a second cylinder chamber 16 , The first cylinder chamber 14 This is from the piston rod 8th interspersed and designed as an annular chamber.

In the cylinder housing 4 is a partition 18 provided the second cylinder chamber 16 from a pressure relieved third cylinder chamber 20 demarcates. The third cylinder chamber 20 turn is from another second piston 22 from one in the cylinder housing 4 provided pressure chamber 24 separated. The second piston 22 has another second piston rod 26 on top of the pressure chamber 24 interspersed and out of a head 28 of the cylinder housing 4 protrudes. At the second piston rod 26 End is a piston unit 30 intended.

The piston unit 30 is with a spring force over a spring 32 subjected to a Radialbund 34 of the cylinder housing 4 supported. The feather 32 encompasses the cylinder housing 4 starting from the Radialbund 34 ,

For feeding pressure medium into the first or second cylinder chamber 14 . 16 or for discharging pressure medium from the first or second cylinder chamber 14 . 16 is a hydraulic machine 36 intended. This is about a variable speed electric motor 38 can be driven in both directions at different speeds. The hydraulic machine 36 can be used as a hydraulic pump or hydraulic motor. Via a first pressure line 40 is the hydraulic machine 36 with the first cylinder chamber 14 and via a second pressure line 42 with the second cylinder chamber 16 connected. In a respective pressure line 40 . 42 is a valve 44 respectively 46 arranged. A respective valve 44 . 46 serves to control a pressure medium connection between the hydraulic machine 36 and the first and second cylinder chambers, respectively 14 . 16 , A respective valve 44 . 46 is designed here as a 2/2-way valve, wherein a valve spool can be acted upon by a spring force of a valve spring in the direction of an open position and with the actuating force of an actuator in the direction of a closed position. To the one with the second cylinder chamber 16 connected pressure line is a first hydraulic accumulator 48 connected. In the pressure medium flow path between the valve 44 and the first cylinder chamber 14 is a pressure relief valve 50 connected, the output side with a second hydraulic accumulator 52 connected is.

The pressure chamber 24 is via a first check valve 54 to the first pressure line 40 between the valve 44 and the hydraulic machine 36 and a second check valve 56 to the second pressure line 42 in the pressure medium flow path between the valve 46 and the hydraulic machine 36 connected. The check valves 54 and 56 open in each case in a pressure fluid flow direction to the pressure chamber 24 , About the check valves 54 and 56 is in the pressure chamber 24 thus from the hydraulic machine 36 Pressure medium feedable. For connecting the check valves 54 and 56 with the pressure chamber 24 is a pressure line 58 intended.

From the pressure line 58 branches a quick-closing valve 60 off, over that the pressure chamber 24 to the second hydraulic accumulator 52 is depressurable. The quick-closing valve 60 is here as according to the valves 44 and 46 designed. To the pressure medium flow path between the quick-closing valve 60 and the second hydraulic accumulator 52 is the first pressure line 40 via a check valve 62 and the second pressure line 42 via a check valve 64 connected. The check valves 62 and 64 close in this case in a pressure fluid flow direction to the hydraulic accumulator 52 ,

Furthermore, to the pressure line 58 a pressure relief valve 66 connected, via which a pressure in the pressure chamber 24 is limited. On the output side is the pressure relief valve 66 with the second hydraulic accumulator 52 connected.

For controlling the piston unit 30 is about the hydraulic machine 36 either the first cylinder chamber 14 or the second cylinder chamber 16 charged with pressure medium and of the corresponding another cylinder chamber 14 . 16 pressure medium is released. Thus, the cylinder housing 4 together with the piston unit 30 postponed. The piston unit 30 is here by the spring force of the valve spring 32 and the pressing force of the pressure medium in the pressure chamber 24 clamped. The cylinder housing 4 thus becomes when controlling the piston unit 30 along with this and its piston rod 26 and its piston 22 and the valve spring 32 emotional.

For quick closing of the piston unit 30 just becomes the quick-closing valve 60 opened, bringing pressure from the pressure chamber 24 is discharged, and the piston unit 30 then about the spring force of the spring 32 can be moved into its closed position. This then takes place independently of the position of the cylinder housing 4 ,

According to 2 is not the cylinder housing 4 of the cylinder 2 movable, but the piston 6 , bringing the cylinder housing 4 is fixed. From the piston 6 out extends the first piston rod 8th and a second piston rod 68 , The piston rod 8th and 68 have an equal diameter, bringing the cylinder 2 designed as a synchronous cylinder. The first piston rod 8th penetrates the first cylinder chamber 14 and the second piston rod 68 the second cylinder chamber 16 , At the second piston rod 8th is the radial collar at the end 34 formed, on which the spring 32 can support. The piston rods 8th . 68 and the piston 6 are from a common recess 70 interspersed on the part of the Radial Federation 68 is inserted and in the piston rod 68 ends. In the recess 70 is the second piston 22 guided axially displaceable and limited therein the pressure chamber 24 , Furthermore, the pressure chamber 24 from the front end portion 70 the piston rod 68 limited. The piston rod 26 of the piston 22 passes through the pressure chamber 24 and the front end portion 70 and thus protrudes from the piston rod 68 out. This in turn juts out of the head 28 of the cylinder housing 4 out.

Thus, according to the embodiment in FIG 2 not the cylinder housing 4 but the piston 6 movable by adding pressure medium into the cylinder chamber 14 respectively 16 fed and from the corresponding other cylinder chamber 16 respectively 14 is dismissed. The piston 6 will then be together with the piston 22 and the piston unit 30 and the valve spring 32 postponed. The cylinder chambers 14 and 16 and the pressure chamber 24 are according to the embodiment in 1 to the pressure lines 40 . 42 respectively 58 connected.

3 shows a further embodiment of the invention, in which the piston rod 8th according to the 1 is fixed and the cylinder housing 4 is displaceable. The cylinder housing 4 has in contrast to the embodiment in 1 only the first and second cylinder chamber 14 and 16 on. In contrast, the cylinder housing has 4 one end as a piston 72 provided radial collar. This one is in the area of the head 28 of the cylinder housing 4 intended. The piston 72 is then in one with the piston unit 30 Connected cylinder housing 74 guided. The piston 30 serves at the cylinder housing 74 then as ground, in which case a head 76 of the cylinder housing 74 from the cylinder housing 4 is interspersed and that protrudes from this. Between the head 76 and the piston 72 is the cylinder housing 74 then the pressure chamber 24 limited.

According to the embodiment in 4 is different from 3 another from the piston 6 extending piston rod 78 intended. This has a same diameter as the piston rod 8th on, why the cylinder 2 with the cylinder housing 4 designed as a synchronous cylinder.

Disclosed is a three-chamber cylinder with a cylinder housing and a piston displaceable therein, which has a piston rod. With the piston, a first of a second cylinder chamber is separated. If pressure medium is charged into the first or second cylinder chamber and discharge pressure medium from the second or first cylinder chamber, the piston or the cylinder housing is displaced in the axial direction. It is provided a spring which is supported on the displaceable component, ie on the piston or the cylinder housing, and is displaceable together with this. The spring in turn acts on a piston unit with a spring force. The piston unit defines together with the cylinder housing a pressure chamber, via which it can be acted upon to bias the spring with pressure medium.

LIST OF REFERENCE NUMBERS

1

 cylinder arrangement

2

 cylinder

4

 cylinder housing

6

 first piston

8th

 piston rod

10

 ground

12

 fastening device

14

 first cylinder chamber

16

 second cylinder chamber

18

 partition wall

20

 third cylinder chamber

22

 second piston

24

 pressure chamber

26

 second piston rod

28

 head

30

 piston unit

32

 feather

34

 radial collar

36

 hydromachine

38

 electric motor

40

 pressure line

42

 pressure line

44

 Valve

46

 Valve

48

 hydraulic accumulator

50

 Pressure relief valve

52

 hydraulic accumulator

54

 check valve

56

 check valve

58

 pressure line

60

 Quick-closing valve

62

 check valve

64

 check valve

66

 Pressure relief valve

68

 piston rod

70

 end

72

 piston

74

 cylinder housing

76

 head

78

 piston rod

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1283370 A2 [0004]

Claims (15)

Cylinders with a cylinder housing ( 4 ) and a piston arranged therein ( 6 ), from which a piston rod ( 8th ), wherein the piston ( 6 ) a first of a second cylinder chamber ( 14 . 16 ) separates, in each of the pressure medium chargeable and of which each pressure medium is discharged, to the piston ( 6 ) or the cylinder housing ( 4 ) in the axial direction, characterized in that a spring ( 32 ) provided on the displaceable piston or on the displaceable cylinder housing ( 4 ) and a piston unit ( 30 ) acted upon by a spring force, via this together with the displaceable piston ( 6 ) or the displaceable cylinder housing ( 4 ) a pressure chamber ( 24 ), over which the piston unit ( 30 ) for tensioning the spring ( 32 ) can be acted upon with pressure medium. Cylinder according to claim 1, wherein the piston unit ( 30 ) a second piston ( 22 ) with a second piston rod ( 26 ), with which the piston unit ( 30 ), wherein the second piston ( 22 ) in the displaceable cylinder housing ( 4 ) or the displaceable piston ( 6 ) the pressure chamber ( 24 ), which is separated from the second piston rod ( 26 ) is interspersed. Cylinder according to claim 2, wherein the first piston rod ( 8th ) on the one end face of the cylinder housing ( 4 ) and the second piston rod ( 26 ) on the other end face of the cylinder housing ( 4 ) protrudes. Cylinder according to claim 2 or 3, wherein the second piston ( 22 ) with its from the first piston ( 6 ) pioneering face the pressure chamber ( 24 ) and with its other end face a cylinder chamber ( 20 ) in the displaceable piston ( 6 ) or the displaceable cylinder housing ( 4 ) limited. Cylinder according to claim 1, wherein the piston unit ( 30 ) a second cylinder housing ( 74 ), with which the piston unit ( 30 ), wherein the second cylinder housing ( 74 ) the displaceable first cylinder housing ( 4 ) or the displaceable piston ( 6 ) and the pressure chamber ( 24 ) limited. Cylinder according to claim 5, wherein the displaceable cylinder housing ( 4 ) a piston ( 72 ), which in the second cylinder housing ( 74 ) of the piston unit ( 30 ) the pressure chamber ( 24 ) limited. Cylinder according to one of the preceding claims, wherein the spring ( 32 ) on a radial collar ( 34 ) of the displaceable piston ( 6 ) or the displaceable cylinder housing ( 4 ) is supported. Cylinder arrangement with a cylinder according to one of the preceding claims, wherein pressure medium from the pressure chamber ( 24 ) via a quick-closing valve ( 60 ) can be discharged. Cylinder arrangement according to claim 8, wherein a hydraulic machine ( 36 ) is provided, which via a first pressure line ( 40 ) with the first cylinder chamber ( 14 ) and via a second pressure line ( 42 ) with the second cylinder chamber ( 16 ) is fluidically connected, and wherein the pressure chamber ( 24 ) via a valve ( 54 . 56 ) with the first pressure line ( 40 ) is connectable. Cylinder arrangement according to claim 9, wherein the pressure chambers ( 24 ) via another valve ( 54 . 56 ) with the second pressure line ( 42 ) is connectable. Cylinder arrangement according to claim 10, wherein the valves ( 54 . 56 ) as in pressure fluid flow direction to the pressure chamber ( 24 ) opening check valves ( 54 . 56 ) are formed. Cylinder arrangement according to one of claims 8 to 11, wherein the pressure chamber ( 24 ) to a pressure relief valve ( 66 ) connected. Cylinder arrangement according to one of claims 8 to 12, wherein with the pressure medium flow path between the quick-acting valve ( 60 ) and a hydraulic accumulator connected to the first and / or the second pressure line in each case via a valve ( 62 , 64 ) is fluidically connectable. Cylinder arrangement according to claim 13, wherein the valves ( 62 . 64 ) as in pressure fluid flow direction to the pressure medium flow path closing check valves ( 62 . 64 ) are formed. Cylinder arrangement according to one of claims 8 to 14, wherein the hydraulic machine ( 36 ) via an electric actuator ( 38 ) Variable speed in both directions can be driven.

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