EP3175123A1

EP3175123A1 - Hydraulic spindle

Info

Publication number: EP3175123A1
Application number: EP15747138.4A
Authority: EP
Inventors: Andreas Guender; Johannes Schwacke
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-07-31
Filing date: 2015-07-29
Publication date: 2017-06-07
Anticipated expiration: 2035-07-29
Also published as: CN107076177B; WO2016016310A1; CN107076177A; ES2820871T3; DE102014215080A1; EP3175123B1

Abstract

The invention relates to a compact hydraulic spindle having a cylinder. Inside said cylinder, a pump for controlling the cylinder is mounted. The pump is provided in a cavity of the cylinder. The cylinder is designed as a differential-type double rod cylinder.

Description

Hydraulic axis

description

The invention is based on a hydraulic axis according to the preamble of

Claim 1.

Such hydraulic axes are used, for example, in the power plant sector, in particular in gas and steam turbine plants. They can then be used, for example, when operating a valve body, which is used to control a

Pressure medium connection between a waste heat boiler and a steam turbine is used, with a quick closing should be possible. The trend in this area is self-sufficient and compact valve or linear actuators with such an axis, which in addition to a cylinder in particular an electric control unit, an electric motor, a hydraulic pump and a hydraulic control block with valves. The most bulky components are arranged in a known and relatively compact solution to the cylinder housing of the hubausführenden cylinder, the valve drive then overall high weight and still a comparatively high

Has space requirements.

In contrast, the invention has for its object to provide a hydraulic axis, which have a compact and low space requirement

Valve drive leads.

The object is achieved with a hydraulic axis according to the features of

Claim 1. Other advantageous developments of the invention are the subject of further subclaims.

According to the invention, a compact hydraulic axle has a cylinder. This can be actuated via a pump (hydraulic pump). Advantageously, the pump is installed in a cavity of the cylinder. The cylinder is designed here as a synchronous cylinder, which is designed in differential construction. Thus, a differential cylinder is provided in differential design with an integrated pump. This solution has the advantage that a self-sufficient valve drive with the

hydraulic axis according to the invention is possible in the control and a quick closing of gas and steam turbines. By integrating the pump in the

Cavity of the cylinder, a housing of the pump, a control block can be saved together with valves and a piping. A hydraulic energy generated in the pump can be without or with little deflections and no or little

Flow losses are used to drive the cylinder. Since the

Gleichgangzylinder is formed in differential design, it is advantageously shorter than a conventional Gleichgangzylinder seen in the axial direction, since only one side of a piston rod extends from a piston and thus no clearance for a further piston rod of the Gleichgangzylinders provided or kept free. Thus, by the Gleichgangzylinder in differential design space for the integration of the pump provided. Furthermore, it is advantageous that the cylinder is volume balanced, which in contrast to a differential cylinder no hydraulic accumulator for

Volume compensation is necessary. Thus, by the hydraulic axis according to the invention, a reduction of the components by combination of cylinder and

Pump functions enabled. As a result, the hydraulic axis is advantageously optimized in terms of weight and space, and combines advantages of the electrical with advantages of the hydraulic linear drives when the drive of the pump takes place via an electric motor. In a further embodiment of the invention, the cylinder has an outer cylinder tube which engages around an inner cylinder tube. The inner cylinder tube is preferably fixedly connected to the outer cylinder tube. Furthermore, the cylinder tubes are preferably arranged coaxially with one another. In terms of device technology, the cavity can be formed with the pump in the inner cylinder tube. The cylinder tubes can, in particular the outer cylinder tube with his

Inner circumferential surface and the inner cylinder tube with its outer circumferential surface, a

Limit annulus. In this, a, in particular annular, piston can be arranged axially displaceable. From this preferably extends an approximately hollow cylindrical piston rod, whereby the piston is preferably connected only on one side with a piston rod. The piston rod can pass through a closure device of the cylinder and on a side facing away from the piston of the

Closing device for limiting a first cylinder chamber to be closed. Furthermore, the piston may define a second cylinder chamber on the piston rod side on a side of the closure device facing the piston.

A pressure in one or both cylinder chambers can each have a

Limited pressure relief valve. For example, a pressure relief valve may be provided that from a certain pressure in the second cylinder chamber, a pressure medium connection between the second cylinder chamber and the first

Cylinder chamber opens. Alternatively or additionally, it is conceivable that another

Pressure relief valve or the same pressure relief valve opens a pressure medium connection between the first cylinder chamber and the second cylinder chamber from a certain pressure in the first cylinder chamber.

Diametrically to the closure device, the cylinder is additionally closed by a cylinder bottom. To close the piston rod, a piston cover may be provided. The differential type differential cylinder thus has an inner cylinder tube, an outer cylinder tube, a cylinder bottom and a shutter device. Therein, the piston is arranged with a piston rod and a piston cover.

In a further embodiment of the invention, two chamber sections in the second cylinder chamber are separated by the hollow cylindrical piston rod. Preferably, thereby an outer annular chamber portion and an inner annular chamber portion are formed. A connection of the chamber sections can take place via a flow path. In the axial direction, the chamber sections or can the second

Cylinder chamber be limited by the piston and the closure device. The fluidic connection of the chamber sections is carried out device technology simply via at least one introduced into the piston rod recess. This is, for example, a hole, a slot or a groove. Advantageously, the recess is in this case arranged adjacent to the piston, which even at a in the

Substantially fully extended piston rod, the fluidic connection of the chamber sections is not separated.

Thus, the cylinder chambers are volume-balanced, a second cylinder chamber limiting effective area of the piston and the first cylinder chamber limiting effective area of the piston rod are about the same size.

To drive the piston can be conveyed from the first cylinder chamber into the second cylinder chamber and vice versa simply via the pump pressure medium. Becomes

Promoted pressure medium from the first to the second cylinder chamber, the piston rod is retracted. In the reverse direction, the piston rod extends.

The pump can also be driven in a simple manner via a drive shaft by a drive unit, which is preferably an electric motor, as already explained above. The drive unit is preferably arranged at least in sections within the inner cylinder tube and may alternatively be flanged to the cylinder from the outside. Thus, the hydraulic axis is substantially self-sufficient and requires only a power supply, for example electrical energy, for driving the drive unit.

The drive shaft is coupled to the pump and via the inner cylinder tube to

Drive unit and / or led to the outside. The drive shaft is coupled, for example via a coupling with the pump. The pump is preferably a piston pump. Alternatively, it is conceivable to provide a gear pump. The piston pump is further preferably in

Swash plate construction formed. A drive shaft of the piston pump penetrates in particular a swash plate, a cylinder drum and a distributor plate of the piston pump axially and is rotatable in the inner cylinder tube via bearings, in particular Rolling bearings, stored. About a positive connection, for example via a

Keyway, the drive shaft may be connected to the cylinder drum. The cylinder drum is preferably supported on its side facing away from the swash plate side on the distributor plate.

The closure device, which is penetrated by the piston rod, an outer annular, the piston rod embracing closure element, in particular an outer cylinder cover, and an inner, disposed within the Kolbestange

Closing element, in particular an inner cylinder cover having.

In a further embodiment of the invention can save space in the interior

Closing element may be formed a first fluid channel, which fluidly connects the first cylinder chamber with the pump. Preferably, a second fluid channel is formed, which fluidly connects the second cylinder chamber with the pump. For fluidically connecting the fluid channels to the pump, for example, the distributor plate is located on the inner

Closing element on. The inner closure element is preferably configured essentially in two stages, wherein it is inserted into the inner cylinder tube with a first smaller step and is supported on the front side of the inner cylinder tube via a shoulder formed between the steps.

The pressure relief valve is preferably via a channel in the interior

Closure element connected to the second fluid channel. About the

Pressure relief valve can then be opened a pressure medium connection between the second fluid channel and the first cylinder chamber. The

Pressure relief valve is firmly connected, for example, with the closure element.

The fluid channels are, for example, simply designed as bores in terms of device technology. In a further embodiment of the invention, the distributor plate of the pump has control kidneys, which continue in the inner closure element as closure element-side control kidneys, which are each connected to one of the fluid channels. Here is the

Distributor plate preferably rotatably connected to the inner closure element. To compensate for a change in volume of a pressure medium in the cylinder at

Temperature changes can be provided, in particular smaller, hydraulic accumulators. This can additionally be designed such that it can be used to bias the respective low-pressure region. In terms of device technology, the hydraulic accumulator can be integrated in the inner closure element. So that the hydraulic accumulator can be connected to the respective low-pressure region, the first fluid channel is connected to it via a first check valve closing towards the hydraulic accumulator and the second

Fluid channel via a second to the hydraulic accumulator closing check valve connected to this.

The hydraulic accumulator may be formed in a further embodiment of the invention as a piston accumulator with a spring-biased accumulator piston. The bias is in this case, for example, such that a respective low-pressure region is biased. A

Preload can be for example about 5 bar here. The accumulator piston of the

Piston accumulator is for example in a blind hole of the inner

Closing element axially guided. For closing the blind hole with respect to the first cylinder chamber, a lid member is provided, which on the inner

Closing element is applied. On the cover element, a memory spring can be supported and act on the accumulator piston with a spring force. Via a leakage channel, the hydraulic accumulator can be additionally connected to the pump for pump leakage. The leakage channel extends, for example, starting from the blind hole, in particular coaxially to this, towards the drive shaft of the pump and can continue therein.

Advantageously, in the cylinder bottom of the cylinder, an optical rangefinder

be provided, which may also be redundant. About the rangefinder, a distance to the piston is preferably measurable, since in the cylinder chamber, which is bounded by the piston and the cylinder bottom, no pressure medium, but for example a gas (air) may be provided. The optical rangefinder is, for example, a laser rangefinder, which makes a simple way

Position measuring system can be integrated.

In the following, preferred embodiments of the invention will be described with reference to FIG

Drawings explained in more detail. Show it: 1 shows a schematic representation of the hydraulic axis according to the invention according to a first embodiment,

FIG. 2 is a perspective view of the hydraulic axis in a longitudinal section according to a second embodiment,

3 shows in a longitudinal section a portion of the hydraulic axis of Figure 2 in the region of the pump and the piston and

4 shows an enlarged detail of Figure 3.

According to FIG. 1, a hydraulic axis with a cylinder 1 is provided. This has an outer cylinder tube 2, which surrounds an inner cylinder tube 4. About a flange 6, the cylinder 1 is fixed in position. About an outer circumferential surface 8 of the inner cylinder tube 4 and an inner circumferential surface 10 of the outer cylinder tube 2, an annular space 12 is limited. In this an annular piston 14 is guided axially displaceable. Axially, the annular space 12 is limited on the one hand by the cylinder base 16 and on the other hand by the cylinder cover 18.

Starting from the piston 14 extends on one side a hollow cylindrical piston rod 20. This passes through the cylinder cover 18 and divides it into an annular outer cylinder cover 22 and an outer closure element and an inner annular cylinder cover 24 and an inner closure element. The piston rod 20 is closed on its side facing away from the piston 14 axially side by a piston cover 26.

According to Figure 1, the piston rod 20 extends in the radial direction approximately centrally starting from the piston 14. The piston rod 20 defines together with the piston cover 26 and the cylinder cover 18 via an active surface 27, a first cylinder chamber 28. A second cylinder chamber 30 is the piston 14 piston rod side over an active surface 29 limited. The cylinder chamber 30 is axially penetrated by the piston rod 20, whereby the

Piston rod 20, the second cylinder chamber into an inner chamber portion 32 and an outer chamber portion 34 separates. For the fluidic connection of the chamber sections 32 and 34, a bore 36, which is formed adjacent to the piston 14, is introduced into the piston rod 20.

In a cavity 38 of the cylinder 1, which is bounded by the inner cylinder tube 4, a pump 40 is inserted. To drive the pump is a drive unit 42nd

Provided (electric motor), which is also inserted into the inner cylinder tube 4. The pump 40 is thus seen in the axial direction between the drive unit 42 and the Cylinder cover 18 arranged. The pump 40 is fluidly connected to both cylinder chambers 28 and 30. It can thus pressure fluid from the cylinder chamber 28 in the

Promote cylinder chamber 30 and vice versa of the cylinder chamber 30 in the cylinder chamber 28 to move the piston 14 together with the Kolbestange 20 axially.

The cylinder shown in Figure 1 is as a differential cylinder in differential construction

configured, whereby only a single piston rod 20 is required. The piston 14 can then with its side facing away from the piston rod 20 side 44 another

Limit cylinder chamber 46, which is connected, for example, with an atmosphere. Since no pressure medium has to be provided in the cylinder chamber 46, an optical rangefinder for measuring the distance of the piston 14 can preferably be integrated in this area.

According to Figure 2, a further embodiment of the cylinder 1 is shown. Here, a drive unit 48 in the form of an electric motor outside of the cylinder tubes 2 and 4 is arranged. The drive unit 48 is in this case flanged to the cylinder bottom 16 coaxial with the cylinder tubes 2 and 4. A drive shaft 50 of the drive unit 48 dives from the outside into the inner cylinder tube 4 and extends up to a drive shaft 52 of the pump 40. Via a coupling, the drive shaft 52 and the drive shaft 50 are coupled together.

According to Figure 3, the piston 14 has outside and inside each have a sliding ring and a

Poetry. In contrast to FIG. 1, the piston rod 20 is not arranged centrally on the piston 14 in the radial direction, but is offset inwards in the radial direction.

The piston cover 26 is radially stepped back and thus formed in two stages. With its smaller step 54, it is inserted into the piston rod 20 and lies with its on

Step transition formed shoulder 56 on an end face of the piston rod 20 at. Via a screw connection, the piston cover 26 is screwed to the piston rod 20. Between the small step 54 and an inner circumferential surface 58 of the piston rod 20, a seal is introduced. The outer cylinder cover 22 is configured annular and also radially stepped back, so that it is designed step-shaped. With his small step 60, he dives into the annulus 12 and limits the front side of the outer chamber portion 34. Between a

Inner circumferential surface 8 of the outer cylinder tube 2 and an outer circumferential surface of the step 60, a sealing means is provided. The outer cylinder cover 22 further has a cylindrical, approximately coaxial with the cylinder 1 extending inner circumferential surface 62, which serves to guide the piston rod 20. Seen in axial direction in series are in the

Inner lateral surface 62 introduced sealant. Seen in the axial direction, a sliding ring is arranged between the sealing means. A diameter of the outer cylinder cover 22 is selected to be larger than a diameter of the outer cylinder tube 2, whereby it projects beyond the outer cylinder tube 2 in the radial direction. About a screw is the

Cylinder cover 22 bolted to the outer cylinder tube 2.

The inner cylinder cover 24 is cylindrical and radially stepped back, thus having a first small step 64 and a second large step 66. The first stage 64 is in this case inserted into the inner cylinder tube 4. Via a formed between the steps 64 and 66 shoulder 68 of the inner cylinder cover 24 abuts an end face of the inner cylinder tube 4. According to FIG. 4, the inner cylinder cover 24 has a second fluid channel 70, which connects the inner chamber section 32 to the pump 40. Furthermore, in the inner cylinder cover 24, a first fluid channel 72 is formed, which connects the first cylinder chamber 28, see also FIG. 3, to the pump 40. The second fluid channel 70 is formed by a radial bore 74, which is introduced radially from the outside into the cylinder cover 24 and opens into an axial blind hole 76, which is one of the pump 40th

pioneering side ago introduced into the cylinder cover 24. The blind hole 76 is connected at the end to a cylinder cover 24 formed in the control kidney 78. The axial blind hole 76 is in this case formed at a parallel distance from a longitudinal axis of the cylinder 1. For the first fluid channel 72, an axially extending blind hole 80 is introduced from the first cylinder chamber 28, which opens into a radial bore 82. The radial bore 82 is also introduced radially from the outside into the cylinder cover 24 and extends approximately coaxially with the other radial bore 74. Die

Radial bore 82 is in this case closed to the outside via a closure element. It also opens into an axially extending blind hole 84, which accordingly the blind hole 76 is configured and at a parallel distance to this and the

Longitudinal axis of the cylinder 1 is arranged. The blind hole 84 then opens in a further control kidney 86. In the area of the second stage 66 and in the area of

Radial bores 82 and 74, the cylinder cover 24 is radially stepped back to the

Radial bore 74 with the inner chamber portion 32 to connect. A

Outer lateral surface 88 of the second stage 66 serves as a guide surface for the piston rod 20 and opposite to the sealing means of the outer cylinder cover 22 also has sealing means, wherein seen in the axial direction between the sealing means, a sliding ring is provided.

Coaxial with the cylinder cover 24, a further large blind bore 90 is introduced into this, the bore bottom 92 is spaced in the axial direction to the radial bores 74 and 82. The blind hole 90 serves to form a hydraulic accumulator which is designed as a piston accumulator 94. This has an axially displaceable in the

The sleeve-shaped accumulator piston 96 is acted upon by a spring force of a storage spring 98, which is supported on a bolted to the cylinder cover 24 cover member 100 and immersed in the accumulator piston 96. The cover element 100 in this case closes the blind hole 90. The blind base 92 has the blind holes 76 and 84 for the fluid channels 70 and 72 introduced, which intersect the radial bores 74 and 82, respectively. In the

Blind holes 76 and 84 is seen in the axial direction between the radial bores 74 and 82 and the bottom of the hole 92 a check valve 102 and 104 respectively. These close in each case in a flow direction to the blind hole 90th

The blind bore 80 of the first fluid channel 72 is connected to a through-bore through the cover member 100 for fluid communication with the first cylinder chamber 28. Center of the cylinder cover 24, starting from the bottom of the hole 92 is a

Through hole 106 introduced. This is the end radially widened and serves to receive a first roller bearing 108 for a drive shaft 1 10 of the pump 40. In the drive shaft 1 10, a leakage channel 1 12 is introduced into the at least one transverse bore 1 13 opens, via which the leakage channel 1 12 with the leakage side of the pump 40 is connected is. The leakage channel 1 12 opens into the through hole 106 and is connected via this with the piston accumulator 94. According to Figure 3, the pump 40 as

Swash plate pump designed. It has a cylindrical drum 1 14, which is rotatably connected to the drive shaft 1 10. In the cylinder drum 1 14 piston 1 16 are axially guided in piston bores. These are based on a swash plate 1 18 inserted firmly into the inner cylinder tube 4. The rotatable cylinder drum 1 14 in turn is supported with its facing the inner cylinder cover 24 end face on a distributor plate 120, which in turn abuts an end face of the inner cylinder cover 24. The distributor plate 120 is non-rotatably arranged in the inner cylinder tube 4 and has control kidneys which are connected to a respective control kidney 78 and 86, respectively, see Figure 4.

In the swash plate 1 18, a radial shaft seal 122 is provided, which surrounds the drive shaft 1 10. Furthermore, a second rolling bearing 124 in the swash plate 1 18 for supporting the drive shaft 1 10 is arranged.

FIG. 3 shows a bore 36 which radially penetrates the piston rod 20 and thereby connects the two chamber sections 32, 34 of the second cylinder chamber 30 to one another.

The cylinder chambers 28, 30 can be connectable via a pressure limiting valve 126, which opens at a certain pressure in a respective cylinder chamber 28, 30. It would also be conceivable only the pressure in one of the cylinder chambers 28, 30 via a

Limit pressure relief valve or provide a pressure relief valve for a respective cylinder chamber 28, 30. The pressure relief valve 126 is connected via a parallel to the longitudinal axis of the cylinder 1 extending axial bore 128 with the radial bore 74 of the second fluid channel 70. The axial bore 128 extends from the lid member 100 in the inner cylinder cover 24, wherein it completely penetrates the lid member 100 and in the inner cylinder cover 24 in the

Radial bore 74 opens. The pressure relief valve 126 is then connected to the axial bore 128 and preferably fixed to the lid member 100 and thus preferably arranged in the first cylinder chamber 28.

If the pump 40 is driven by the drive unit 48 in a first direction of rotation, it promotes pressure medium from the first cylinder chamber 28, see FIG. 3, via the first fluid channel 72, see FIG. 4, into the second fluid channel 70 If the pump 40 is driven in the opposite direction of rotation, it promotes pressure medium from the chamber sections 32 and 34 via the second fluid channel 70 in the first fluid channel 72 and further into the first

Cylinder chamber 28.

Disclosed is a compact hydraulic axle with a cylinder. In this a pump for driving the cylinder is arranged. The pump is in this case provided in a cavity of the cylinder. The cylinder is designed as a differential cylinder differential cylinder.

LIST OF REFERENCE NUMBERS

1 cylinder

2 outer cylinder tube

4 inner cylinder tube

6 flange

8 outer circumferential surface

10 inner circumferential surface

12 annulus

14 pistons

16 cylinder bottom

18 cylinder cover

20 piston rod

22 outer cylinder cover

24 inner cylinder cover

26 piston covers

27 effective area

28 first cylinder chamber

29 effective area

30 second cylinder chamber

32 inner chamber section

34 outer chamber section

36 bore

38 cavity

40 pump

42 drive unit

44 piston side

46 cylinder chamber

48 drive unit

50 drive shaft

52 drive shaft step

shoulder

Inner surface area

step

Inner surface area

first stage

second step

shoulder

second fluid channel

first fluid channel

radial bore

Blind hole

kidney control

Blind hole

radial bore

Blind hole

kidney control

Outer casing surface

Blind hole

hole bottom

Hydraulic accumulator / piston accumulator

accumulator piston

storage spring

cover element

check valve

Through hole first rolling bearing

drive shaft

leakage channel cross hole

cylinder drum

piston

swash plate

distribution plate

Radial shaft seal second rolling bearing

Pressure relief valve

axial bore

Claims

claims

Hydraulic axis with a cylinder (1), which is controllable via a pump (40), characterized in that the pump (40) is installed in a cavity (38) of the cylinder (1), and the cylinder (1) is a synchronous cylinder in differential construction.

Hydraulic axle according to claim 1, having an outer cylinder tube (2) in which an inner cylinder tube (4) is arranged, wherein in the inner cylinder tube (4) the cavity (38) is formed with the pump (40).

Hydraulic axle according to claim 2, wherein the cylinder tubes (2, 4) delimit an annular space (12) in which a piston (14) is arranged axially displaceable, from which extends a hollow cylindrical piston rod (20) comprising a piston

Locking device (18) of the cylinder (1) passes through and on a side facing away from the piston (14) side of the closure device (18) for defining a first cylinder chamber (28) is closed, and wherein the piston (14) piston rod side, a second cylinder chamber (30) limited.

The hydraulic axle of claim 3, wherein the piston rod (20) radially separates the second cylinder chamber (30) into an outer chamber portion (34) and an inner chamber portion (32), the chamber portions (32, 34) fluidly communicating via a flow path (36 ) are connected.

Hydraulic axle according to one of the preceding claims, wherein the pump (40) via a drive unit (42, 48) is drivable, which is disposed within the inner cylinder tube (4) or which is flanged to the cylinder (1).

A hydraulic axle according to any one of the preceding claims, wherein the pump (40) is a swash plate type piston pump.

7. Hydraulic axle according to one of claims 3 to 6, wherein the

Closure device (18) an outer annular piston rod (20) encompassing closure element (22) and an inner disposed within the piston rod (20) closure element (24).

A hydraulic axle according to claim 7, wherein a first fluid passage (72) is formed in the inner shutter member (24) fluidly connecting the first cylinder chamber (28) to the pump (40) and a second fluid passage (70) is formed second cylinder chamber (30) fluidly connects to the pump (40).

Hydraulic axle according to one of the preceding claims, wherein a

Hydraulic accumulator (94) is provided for temperature compensation and / or for biasing a respective low-pressure region.

A hydraulic axle according to claim 9, wherein the hydraulic accumulator (94) is formed in the inner closure member (24).

A hydraulic axle according to claim 9 or 10, wherein the first fluid channel (70) is connected to the hydraulic accumulator (94) via a first check valve (102) closing towards the hydraulic accumulator (94), and wherein the second fluid channel (72) is connected via a second fluid channel towards the hydraulic accumulator (94) closing check valve (104) is connected to the hydraulic accumulator (94).

12. Hydraulic axle according to one of claims 9 to 1 1, wherein the hydraulic accumulator (94) via a leakage channel (106, 1 12) to the pump (40) is connected. 13. Hydraulic axle according to one of the preceding claims, wherein the bottom side of the cylinder (1), a rangefinder is arranged.