EP2325390B1 - Screed and road finisher - Google Patents

Description

The invention relates to a screed according to the preamble of claim 1 and a road finisher according to the preamble of claim 15.

When installing coverings of paving material with a screed towed floating on the paving material by the paver with a paving speed dictated by the paver, installation parameters shall be taken into account which require adjustment adjustments to the paving screed and its sliding screeds. So far, the direction control of each a Ausziehbohle relative to the base plate moving hydraulic cylinder, the so-called black / white way valve technology is applied, ie, a directional control valve with a black / white solenoid (solenoid), which assumes a switching position in the energized state without intermediate positions and a certain Magnetic force generated in the de-energized state, however, without generating magnetic force occupies another switching position. Depending on the switching position of the black / white magnet, the directional control valve either opens at least one flow path completely or closes it. This results in a predetermined velocity of the hydraulic flow rate of the hydraulic cylinder in the respective direction of movement. Although the volume flow can be changed by additional hydraulic measures upstream or downstream of the directional control valve. However, with the usual in screeds black / white valve technology no continuous change or adjustment of the movement speed of the hydraulic cylinder is possible.

The out EP 0 620 319 A known road paver has a screed with the features of the preamble of claim 1. The known paver has for each hydraulic cylinder of the Ausziehbohle in the screed on a magnetic switching valve, which is switched by a controller to extend the retractable screed, retract or hold in position. The magnetic switching valve is a directional control valve for the hydraulic cylinder, the movement speed of which depends exclusively on the delivery pressure provided by the hydraulic system of the road paver or the set delivery flow rate (quantity per unit of time). An individual adaptation of the speed of movement of the hydraulic cylinder is not possible with a magnetic switching valve (passage position / shut-off position).

The out US 5,362,176 A Known road paver has for the hydraulic cylinder of the Ausziehbohle in the screed on a 4/3-way directional control valve by means of two solenoids is switchable between its three switching positions. The solenoids (black / white magnets, ie fully energized: on, de-energized: off) are actuated by a control via relays. The speed of movement of the hydraulic cylinder depends solely on the delivery pressure or the delivery rate of a hydraulic pump; however, can not be individually regulated via the 4/3-way directional control valve.

1. a) Das genaue Ausbilden einer nicht in Fahrtrichtung verlaufenden Naht oder eines seitlichen Abschlusses des Belages erfordert eine relativ langsame Bewegungsgeschwindigkeit bzw. präzise Veränderungen der Bewegungsgeschwindigkeit des Hydrozylinders zumindest einer Ausziehbohle.
2. b) Ein seitlicher Anschluss einer Straße oder das Umfahren eines Hindernisses durch Verschieben der Ausziehbohle erfordert abhängig von der Einbaugeschwindigkeit eine gegebenenfalls hohe Bewegungsgeschwindigkeit und einen präzise steuerbaren Geschwindigkeitsverlauf des Hydrozylinders.
3. c) Beim Einbauen eines Belages mit einer nach außen abfallenden Schulter (slope) durch Querneigen des Ausziehbohlen-Glättbleches stellt sich beim Ausschieben der Ausziehbohle ein Höhenversatz zwischen dem Ausziehbohlen-Glättblech und dem Grundbohlen-Glättblech ein, der z.B. durch paralleles Absenken des Ausziehbohlen-Glättbleches kompensiert werden muss, um keine Stufe in der Oberfläche zu formen bzw. den Übergang von der Fahrbahn in die Schulter nicht seitlich zu verlagern. Beispielsweise durch Verwenden einer Referenzschiene, die die Höhenlage und Querneigung des Ausziehbohlen-Glättbleches abbildet und eines Tasters an der Grundbohle, der die Referenzschiene abtastet, könnte der beim Ausschieben entstehende Höhenversatz abgegriffen und durch Ansteuern von Höhenverstellungen des Ausziehbohlen-Glättbleches zumindest theoretisch gleich ausgeglichen werden. Da die Höhenverstellung jedoch im Regelfall mit konstanter und relativ niedriger Geschwindigkeit am Ausziehbohlen-Glättblech abläuft, der entstehende Höhenversatz vom Schulter-Winkel abhängt, der variiert werden kann, wird bei der gegebenen relativ hohen Verschiebegeschwindigkeit der Ausziehbohle der Höhenversatz häufig überkompensiert oder zu wenig kompensiert. Das Entstehen einer Längsstufe in der Oberfläche des Belages und/oder das seitliche Verlaufen des Übergangs von der Fahrbahn in die Schulter lassen sich nicht vermeiden, selbst wenn versucht wird, den Hydrozylinder nur schrittweise zu bewegen. Dies erfordert Nachbesserungen.

A predetermined movement speed of the hydraulic cylinder is disadvantageous, for example, in the following installation situations:

1. a) The exact formation of a non-running in the direction of travel seam or a lateral completion of the covering requires a relatively slow movement speed or precise changes in the speed of movement of the hydraulic cylinder at least one Ausziehbohle.
2. b) A lateral connection of a road or the circumvention of an obstacle by moving the extension screed requires depending on the installation speed optionally high speed of movement and a precisely controllable speed profile of the hydraulic cylinder.
3. c) When installing a covering with an outwardly sloping shoulder (slope) by Querneigen the Ausziehbohlen-Glättbleches arises when pushing the Ausziehbohle a height offset between the Ausziehbohlen-smoothing plate and the screed plate, for example, by parallel lowering of the Ausziehbohlen-Glättbleches must be compensated in order not to form a step in the surface or to shift the transition from the roadway into the shoulder sideways. For example, by using a reference rail which maps the elevation and bank of the Ausziehbohlen-Glättbleches and a probe on the base screed scanning the reference rail, the height offset arising during pushing could be tapped and at least theoretically equalized by driving height adjustments of the Ausziehbohlen-Glättbleches. However, since the height adjustment usually takes place at a constant and relatively low speed on the screed screed plate, the resulting height offset depends on the shoulder angle, which can be varied, the height offset is often overcompensated or under-compensated at the given relatively high displacement speed of the Ausziehbohle. The emergence of a longitudinal step in the surface of the lining and / or the lateral running of the transition from the roadway to the shoulder can not be avoided, even if it is attempted to move the hydraulic cylinder only gradually. This requires improvements.

The invention has for its object to provide a screed and a paver in which it is possible to adjust the movement speed of the hydraulic cylinder for moving the Ausziehbohle when installing a covering to certain and possibly varying installation parameters.

The stated object is achieved with the features of patent claim 1 and claim 15.

The use of a proportional directional control valve with either proportional electrical direct control or proportional electric hydraulic pilot control makes it possible to change or even automatically adjust the movement speed of the hydraulic cylinder and thus the displacement speed of the Ausziehbohle relative to the base board exactly or adapted to at least one installation parameter in proportional valve technology the movement speed of the controlled hydraulic cylinder always exactly corresponds to the current loading of the proportional magnet or has a precisely predeterminable proportionality to the current application. Depending on the current applied, proportional solenoids generate a specific course of the magnetic force or of the magnet lifting and, in contrast to black-and-white actuating magnets, not only switch back and forth between switching positions. The proportional valve technology thus makes it possible to move the respective Ausziehbohle very slowly in the screed for accurate training of a running in working direction seam or a lateral completion of the respective Ausziehbohle or change the movement speed accordingly with a specific profile, and yet to basically set the working width the screed to move the extenders as fast or as slowly as possible. If a side port of a road is to be installed on the pavement or to bypass an obstacle at a certain paving speed, the proportional valve technology for the respective skip can be used to precisely vary the speed of movement as required. If, when installing a shoulder in the lining at a constant speed of the height adjustment of Ausziehbohlen-Glättbleches the height offset when moving the Ausziehbohle automatically compensate, the movement speed of the hydraulic cylinder and thus the Ausziehbohle can be controlled exactly as a function of the set shoulder angle, so that neither a longitudinal step arises nor does the transition from the road to the shoulder drift sideways.

The paver has with the equipment the respective proportional directional control valve electro-hydraulic requirements for to be connected as a working, Ausziehbohlen having screed, which make it possible to precisely control the displacement speed of each Ausziehbohle, modify and / or adapt to certain installation parameters. This results in high quality built-in coverings even in difficult installation conditions.

Although proportional valve technology has been used in mobile hydraulics, for example in crane controls, mast controls of concrete pumps, lifting platforms, industrial trucks and the like for decades, it has a higher cost, complicated electrical control, and a suspected susceptibility to breakdown under extreme working conditions found in a screed or a paver no use for screeds of road pavers, also because the operating personnel specially trained by road pavers to cope with certain installation parameters, and to compensate for the limitations imposed by the black and white valve technique with improvisations and experience.

The proportional valve technology especially for the hydraulic cylinders of the extendable screeds in the screed is useful not only for the non-limiting selection of the listed installation situations, but for all applications in which a precise adjustment and change in the speed of movement of the towed by the paver, but an independent Working unit forming screed is needed to keep the quality of the installed lining as varied and high as possible despite varying or only occasionally occurring installation situations. The proportional valve technology is compatible with a constant pump or a control pump pressure supply, wherein in a constant pump system in non-actuation of a hydraulic consumer, a non-pressurized circulation (via a circulation valve or through the proportional directional control valve) may be provided. Finally, the proportional valve technology in the screed also offers the advantage of being able to control automatic operating sequences conveniently via control systems. Since in the screed with considerable working pressures, e.g. 200 bar or more must be worked, and with large flow rates of, for example 60 l / min, relatively large-sized, powerful proportional solenoids are required for a proportional electrical direct actuation of the directional control valve, so that it may be appropriate proportional directional control valves with proportional electric use hydraulic pilot control, since for proportional feedforward possibly lower pressures and only small quantities of pressure medium are to be mastered, for which kleinbauende and weaker and therefore cheaper proportional solenoids are sufficient.

In an expedient embodiment of the screed, the movement speed of the hydraulic cylinder is adjusted in proportion to a given speed of movement of at least one other Ausziehbohlen component via the control of the proportional solenoid, for the function of the Ausziehbohlen shift is important. For example, the speed of movement of the hydraulic cylinder is set in proportion to the speed of movement of a vertical and / or transverse drive of the Ausziehbohlen-Glättbleches that generates a substantially constant speed of movement. This requires, for example, for adaptation, the speed of movement of the hydraulic cylinder, for example, depending on the bank angle of the Ausziehbohlen-Glättbleches to vary sensitively to compensate for an offset while moving.

In an expedient embodiment, the speed of movement of the hydraulic cylinder is load-independent variable and durable. The proportional valve technology can be particularly easily combined with hydraulic measures that lead to a load independence. This is advantageous because the resistance to movement of the Ausziehbohle example, the Ausschiebehub, wear, the nature of the substrate, the consistency of the paving material, environmental conditions and the like. Depends and may vary. Thanks to the load independence in the control of the movement speed of the hydraulic cylinder, these influences can not falsify the predetermined by the current application of the proportional solenoid movement speed.

The proportional valve technology for the hydraulic cylinder of Ausziehbohlen is expediently used in a screed at the operable with a given movement speed hydraulic cylinder and / or spindle drives with hydro or electric motors for height and / or roll adjustment of Ausziehbohlen-Glättbleches at least relative to the base screed plate are provided. The given speed of such drives has thanks to the proportional valve technology for the hydraulic cylinder of the Ausziehbohlen shift no adverse effect in adapting to certain installation parameters or changing installation situations more. The height and / or roll adjustment of the Ausziehbohlen-Glättbleches can be made different here. In one embodiment, to adjust the bank angle, the entire guide system for the pullout bed is adjusted relative to the base board. In another embodiment, the guide on which the Ausziehbohle is moved, fixed parallel to the screed plate of the base board in this. The extractor screed plate is adjusted only relative to the pull-out, either in the vertical position or in the bank or only in the altitude, in which case the bank angle is changed by an additional adjustment.

For the proportional directional control valve, several construction methods are available. Thus, the proportional directional control valve can be designed as a seat valve or slide valve. A seat valve is characterized by a leak-free shut-off position and precisely predeterminable actuating forces. A spool valve allows very precise control, but works with inevitable leakage. As another alternative, the proportional directional control valve could also be a two-way or three-way flow control valve, which works with a proportional or directly controlled by the proportional solenoid control orifice.

In an expedient embodiment, in a screed associated control block of the electro-hydraulic control at least for the respective Ausziehbohlen-displacement hydraulic cylinder between two working ports and a pressure source with associated tank a 4/3-way proportional pressure control valve, preferably in slide construction and with the tank open zero position, with two oppositely acting proportional solenoids for direct operation provided. The control block contains a minimum number of hydraulic or electro-hydraulic components for each hydraulic cylinder.

In another embodiment, in one of the screed associated control block of the electro-hydraulic control, at least for the respective Ausziehbohlen shift hydraulic cylinder between two working ports and a pressure source with associated tank two 3/2-way proportional pilot pressure control valves each having a proportional solenoid, preferably in slide construction, and a hydraulically pilot operated 4/3-way pressure control valve, preferably in slide design and open to the tank neutral position provided, each 3/2-valve is associated with a pressure pilot control of the 4/3-valve. Although more hydraulic or electrohydraulic components are required in this control block than in the other embodiment, smaller and cheaper proportional solenoids can be used.

It is expedient for the 4/3 valve to be assigned a pressure compensator on the pressure side and a load-holding valve for the work connection side, wherein the two load-holding valves can be opened in a cross-over manner. The pressure compensator makes it possible to operate the proportional directional control valve independently of the load, because the pressure compensator keeps the pressure difference set at the proportional directional control valve by the application of current to the proportional magnet constant, independently of fluctuations in the supply pressure or the working pressure in the hydraulic cylinder, and thus keeps the speed of movement of the hydraulic cylinder constant. The load-holding valves generate a hydraulic blockage of the hydraulic cylinder in the respectively set shift position and immediately release their load-holding function as a function of pressure, when a movement of the hydraulic cylinder is controlled.

The pressure compensator is expediently acted on the control side by a control spring and a, preferably via a shuttle valve, tapped load pressure signal and closing control side by the inlet pressure of the 4/3-valve. In this way, the pressure balance determine changing pressure conditions in the hydraulic cylinder or on the pressure source and intervene accordingly regulating. This is also expedient if several hydraulic consumers are supplied and controlled by a common pressure source.

For safety reasons, at least one working port of the hydraulic cylinder should be protected by a pressure relief valve to the tank, which performs, for example, a shock valve function, if the pullout accidentally moves against an obstacle or to stop.

In an expedient embodiment, the control block in addition to the proportional directional control valves of the hydraulic cylinder for Ausziehbohlen-displacement and other hydraulic consumers in the screed as the hydraulic cylinders and / or hydraulic motors for Ausziehbohlen-Smoothing plate height and / or -Verneigungsverstellung assigned, solenoid-operated directional control valves, and is the control block connected to a common pressure source and also to a common electro-hydraulic control. The pressure source, the tank and the electrohydraulic control, as well as the control block, can be located in the paver. At least the control block could alternatively be accommodated in the screed.

Expediently, the proportional solenoids are assigned electrical proportional amplifiers in the electrohydraulic control, the advantages of which are to keep the application current for the proportional magnet constant regardless of the supply voltage and of thermally induced changes in resistance of the coil of the proportional magnet. Furthermore, this results in a better EMC characteristic and the possibility of use within a wide temperature range.

In an expedient embodiment, the electrohydraulic control system comprises an automatic control section, preferably optionally activatable, for linking the actuation of the proportional solenoids with the motion control of a further extending screed component movement. The automatic control section adjusts, for example, the application of current to the respective proportional magnet in exact association with a movement control of the further extending screed component in order to carry out an individual adaptation to a given installation situation. Alternatively, the energization of the proportional solenoid and the control of the further movement can be linked on the operator side. The control of movements in the screed may be performed by the paver and / or for example an exterior steering position on the screed be, for example, even by wireless route, eg by radio transmission or the like., By an operator off the paver and the screed or possibly even from the Internet using, for example, the Bluetooth or WLAN technology. At least the electrical or electronic components, such as the proportional magnets, and possibly provided feedback sensors can be integrated in a bus system, eg a CAN bus, of the paver.

Fig. 1

eine schematische Seitenansicht eines Straßenfertigers mit einer Einbaubohle beim Einbauen eines Belages,

Fig. 2A, B, C

verschiedene Beispiele für einzubauende Beläge,

Fig. 3

eine schematische Vorderansicht eines Teils einer Ausführungsform einer Einbaubohle in einer Einbausituation,

Fig. 4

die Ausführungsform von Fig. 3 in einer anderen Einbausituation,

Fig. 5

eine schematische Vorderansicht eines Teils einer weiteren Ausführungsform einer Einbaubohle,

Fig. 6

ein schematisches Steuersystem für die Ausführungsform der Einbaubohle der Fig. 3 und 4,

Fig. 7

ein schematisches Steuersystem für die Ausführungsform der Einbaubohle von Fig. 5,

Fig. 8

ein Blockschaltbild eines Steuerblockes, passend zu den Fig. 3 bis 5, und

Fig. 9

ein Blockschaltbild eines Steuerblockes einer anderen Ausführungsform, pas- send zu den Fig. 3 bis 5.

With reference to the drawings, embodiments of the subject invention will be explained. Show it:

Fig. 1

a schematic side view of a paver with a screed when installing a coating,

Fig. 2A, B, C

various examples of coverings to be installed,

Fig. 3

FIG. 2 is a schematic front view of part of an embodiment of a screed in an installation situation; FIG.

Fig. 4

the embodiment of Fig. 3 in another installation situation,

Fig. 5

a schematic front view of a part of another embodiment of a screed,

Fig. 6

a schematic control system for the embodiment of the screed of Fig. 3 and 4 .

Fig. 7

a schematic control system for the embodiment of the screed of Fig. 5 .

Fig. 8

a block diagram of a control block, matching the Fig. 3 to 5 , and

Fig. 9

FIG. 4 is a block diagram of a control block of another embodiment, which corresponds to FIG Fig. 3 to 5 ,

Fig. 1 schematically illustrates a paver F with a screed B when installing a covering 24 of paving material 15 on a substrate 14, wherein the paver F at a paving speed V moves.

The paver F has a chassis 1 with a chassis 2 and a front bunker 3 for paving material. Behind the bunker 3 is a prime mover source, e.g. a diesel engine 4, arranged in the chassis 1, which drives via a pump distributor gear 5, at least one hydraulic pump 6, which supplies a hydraulic system 9, in which at least one control block is arranged with at least one proportional directional control valve, not shown. The screed B is connected to Zugholmen 10, which are connected to draw points 11 of the chassis 1. The tow points 11 can be adjusted by hydraulic motors 12 in height. The road paver F has a driver's cab 7 with a control panel 8, in which at least part of an electro-hydraulic control S for the screed B can be placed. At the rear end of the chassis 1, a transverse distribution device 13 is provided for the built-in material 15, which is conveyed backwards from the bunker 3 and dropped on the ground 14. The screed B forms from the paving material 15, the covering 24 with a certain thickness, which can vary in the direction of travel or transverse to the direction of travel. The built-in material 15 is compacted and leveled in the built-in lining 24 (by precompacting and / or high-compression devices of the screed B, not shown).

The screed B has a base board 16 of a certain width, on which, for example, an outside control stand 17 can be attached. Also, the exterior control station 17 may include a similar or similar electrohydraulic control S '. The electrohydraulic controls S, S 'are connected to the hydraulic system 9 and serve to provide movable working components of the screed B, e.g. to operate hydraulically.

On the base board 16 grundbohlenfeste guide means 18 are provided, on which Ausziehbohlen 19 relative to the base board 16 and transversely to the direction of working back and forth are arranged herverschiebbar. To move each Ausziehbohle 19 at least one hydraulic cylinder 20 is provided, which is supported in the base 16 on the one hand and in the Ausziehbohle 19 on the other. The hydraulic cylinders 20 serve to change the working width of the screed B or of the built-in covering 24. The base screed 16 has at least one screed plate 21 which rests on the paving material 15. Each Ausziehbohle 19 has at least one screed plate 22. The screed B is appropriate employed with a positive angle α relative to the ground 14, while being dragged floating on the paving material 15. The attack angle α determines, for example, the lining thickness of the covering 24. In each Ausziehbohle 19 are height and / or Bank tilt adjustment means 23 for the screed screed plate 22 included to adjust the Ausziehbohlen-screed plate 22 relative to the guide means 18 in height and / or to tilt transversely to the direction of travel (a bank is required when the Ausziehbohle 19 a lateral shoulder in the Lining 24). The devices 23 may have as drives hydraulic cylinders or hydraulic motors, which are supplied by the hydraulic system 9, or electric motors. Usually, the actuated devices 23 generate a substantially constant speed of movement of the Ausziehbohlen-Glättbleches 22nd

The coating 24 in Fig. 2A has over the working width an at least substantially flat top 25. In Fig. 2B the lining 24 has a roof profile 26 (this is the base board 16 according to the Fig. 3 to 5 subdivided into two basic screed parts 16a, 16b which can be bent off relative to one another). In Fig. 2C the lining 24 has a flat upper part 25 (or a roof profile 26, not shown), eg as a roadway, and a lateral, downwardly sloping shoulder 26 '(slope) extending from a transition 27 at an angle β to the outer edge of the lining 24 drops. In the Fig. 2A, 2B, 2C indicates X and X1 different working widths. The working width is changed by actuating at least one of the hydraulic cylinders 20 for displacing at least one of the Ausziehbohlen 19th

Will be in the lining 24 in Fig. 2C increases the working width from X to X1, then by controlling the means 23 and the hydraulic cylinders 20, the transition 27 (the width of the road) must be kept and only the width of the shoulder 26 'should increase. The in the Fig. 2A to 2C indicated changes in the working width can also be controlled when driving around an obstacle or when forming a seam or a lateral conclusion.

Fig. 3 shows the screed B (a part of it) in a schematic view in the direction of travel. The base pile 16 consists of two equal wide base screed parts 16a, 16b, which (not shown in detail), for example, relative to each other are bent to selectively the roof profile 26 of Fig. 2B or the flat top 25 of Fig. 2A or Fig. 2C to shape. The screed-fixed guide means 18 are parallel to the screed smoothing plate 21 and guide the Ausziehbohle 19 during displacement movements controlled by the hydraulic cylinder 20 with respect to the base pile fixed displacement direction. Pro Ausziehbohle 19, for example, two height and / or Querverstellinrichtungen 23 (with hydraulic cylinders, spindle drives with hydraulic motors or electric motors, or the like) provided to the altitude of the Ausziehbohlen-Glättbleches 22 relative to Baseboard screed 21 to be able to adjust, which, for example, when changing in Fig. 1 shown attack angle α is required because the mounted on the rear side of the base beam 16 Ausziehbohle 19 has a greater distance from the towing point 11 than the base board 16 and moves differently than this. The screed in Fig. 3 builds, for example, with the base board 16 and the partially pushed-Ausziehbohle 19 the covering 24 of Fig. 2A one.

Fig. 4 illustrates that the Höhenverstellungs- and / or Querungsverstelleinrichtungen 23 for the Ausziehbohlen-smoothing plate 22 can also be used to adjust the bank of the Ausziehbohlen-Glättbleches 22 with the angle β of the shoulder 26 ', if the covering 24 of Fig. 2C is installed. In order to keep the transition 27 stationary, the height offset Y1 of the Ausziehbohlen-Glättbleches 22 must be compensated with respect to the Grundbohlen-Glättblech 21 by adjusting the angle β when increasing the working width, for example from X to X1 by the Ausziehbohlen-Glättblech 22 parallel to itself itself is lowered. In order that the transition 17 remains stationary in the transverse direction relative to the base beam 16, the movement speed of the hydraulic cylinder 20 must be adjusted as a function of the angle β for a given speed of movement of the height adjustment of the Ausziehbohlen-Glättbleches 22. For this reason, and also for avoiding obstacles or forming precise seams or terminations, therefore, the proportional valve technology for the screed B is used to control the movement speed and / or direction of the hydraulic cylinder 20, as shown in FIG 8 and 9 explained.

In Fig. 5 serve the means 23 only for height adjustment of the Ausziehbohlen-Glättbleches 22 and an intermediate frame 28 'relative to the screed smoothing plate 21 (by means of, for example, a common drive 23'). A bank of the Ausziehbohlen-Glättbleches 22 with the angle β can be selected by a further, separate drive 28 relative to the intermediate frame 28 '. If the working width is increased from X to X1, the devices 23 or the drive 23 'are displaced with a substantially constant speed of movement of the Ausziehbohlen-Glättbleches 22 and intermediate frame 28', so that for locating the transition 27, the movement speed of the hydraulic cylinder 20 depends must be adjusted by the size of the selected angle β. Again, the proportional valve technology is used for speed control.

The electro-hydraulic control S, S 'for the screed B of Fig. 3 and 4 is based Fig. 6 schematically indicated in connection with at least one control block 29 per screed half, to which a common pressure source P and an associated tank on the one hand and the respective hydraulic cylinder 20 and the drives of the devices 23 are connected.

Fig. 7 illustrates the linkage of the electro-hydraulic control S, S 'with a control block 29, per screed half, in which the respective hydraulic cylinder 20 and the drive 23' of the screed B of Fig. 5 are connected. In the control blocks 29 of the 6 and 7 is used for at least the speed control of the hydraulic cylinder 20, the proportional valve technology, as based on the 8 and 9 is explained.

The in the Fig. 1 . 6 and 7 shown control block 29 may be placed in the paver F, for example in the hydraulic system 9 and connected via couplings 61 and hydraulic lines with the screed B and at least the hydraulic cylinder 20. The control block 29 could be located at a suitable location in the screed B or even directly on the respective hydraulic cylinder 20. The control block 29 may be assembled in a plate-row or block construction of individual sections, as for example with reference to 8 and 9 is explained, or modularly constructed of individually mounted hydraulic components.

In the illustrated embodiments of the screed B the Ausziehbohlen 19 are mounted on the rear in working direction rear side of the base pile 16 (rear mount). However, the proportional valve technology can also be used on screeds for the hydraulic cylinders where the screeds are mounted on the front of the screed (front mount).

The control and / or electrical or electronic monitoring of the proportional directional control valve W or of proportional solenoids can be achieved via a bus system common in the road paver today, e.g. a CAN bus, which, if necessary, in conjunction with corresponding sensors and their information ensures high functionality and reliability.

In Fig. 8 the control block 29 comprises at least three assembled sections 30, 31 and 32, the sections 30 and 31 containing proportional directional valves W for at least the two hydraulic cylinders 20 of the screed B, and in the further, not in detail running section 32, for example, black and white Solenoid directional valves W 'for driving Other hydraulic consumers such as the devices 23, 23 'and 28, and the like. The Fig. 3 to 7 can be provided.

Since the sections 30, 31 are substantially identical, only the section 30 will be explained. The section 30 has two working connections 33, 34 for the hydraulic cylinder 20, which is arranged between the extension screed 19 and the base screed part 6a. From the working ports 33, 34 lead working lines 35, 36 to the proportional directional control valve W, wherein the working line 35 is secured via an adjustable pressure relief valve 37 to a connected to a tank T tank line 47, and in both working lines, in this embodiment, hydraulically aufsteuerbare Load holding valves 38 arranged with immediate check valves 39 and between the working lines 35, 36 in a cross-connection 40, a shuttle valve 41 are arranged, which serves for tapping a load pressure signal. The tank line 47 running through the sections 30, 31, 32 is connected to the proportional directional control valve W in the respective section like a pump line 48 common to all sections (pressure source P). In the section 30 of the associated pump line 48 may be arranged as a feed regulator, a pressure compensator 43, the adjustable pressure compensator member by a control spring 44 in the up direction (to open the passage) and parallel to the control spring 44 from a control line 45 with the load pressure signal from the shuttle valve 41st is acted upon, however, in the closing control direction (to shut off) from a control line 46 with the input pressure of the proportional directional control valve W is applied.

The proportional directional valve W is in Fig. 8 a multi-way multi-position spool valve with proportional electrical direct operations by oppositely acting proportional magnets M1, M2, which act directly on a valve element 50 (eg a spool), parallel to springs 42, for example, set the neutral position shown. Specifically, it is a 4/3-way proportional pressure control valve 49 (the pressure control function is indicated by the parallel lines in the symbolic representation) in slide construction with open to the tank neutral position for both working lines 35, 36. The proportional magnets M1, M2 are for example, to the electro-hydraulic control S, S 'connected (in the paver and / or in the exterior control station 17), wherein the electro-hydraulic control S, S' have an automatic control section 60 or may be connected to this, to link the electrical control of the proportional solenoid M1, M2 with a control of a further Ausziehbohlen component movement, for example, the means 23, 23 'in the section 32 of the control block 29, for example, the hydraulic cylinder 20 to adjust with a depending on, for example, the other movement speed selected movement speed. The electrohydraulic control S, S 'basically allows the direction and speed control of each hydraulic cylinder 20, the latter with change of the speed in direct dependence on the current application of the respective proportional magnet M1, M2.

The proportional directional control valve W controls the hydraulic cylinder 20 independent of load, since the pressure compensator 43 independently of the current through the respective proportional solenoid M1, M2 pressure difference across a valve spool 50 keeps constant whether the supply pressure (pressure source P) and / or the working pressure in the respective working line 35, 36 varies, so that always exactly the energization of the proportional magnet M1 or M2 corresponding amount of hydraulic medium per unit time flows, which determines the movement speed of the hydraulic cylinder 20.

The proportional directional valve W (4/3-way valve 49) is in Fig. 8 shown as a one-piece slide valve. The same function could be achieved in two proportional directional control valves. Proportional directional valve W could also be formed as a poppet valve or as one or two two-way or three-way proportional flow control valves (not shown).

The in Fig. 9 shown control block 29 contains for the same functions another embodiment of the proportional directional control valve W. And although the 4/3-way pressure control valve 51 for its spool 50 hydraulic pilot controls 52a, 52b, via control lines 53a, 53b to each a 3 / 2-way proportional pilot pressure control valve 54a and 54b are connected, at which the proportional solenoid M1, M2 act on a pilot valve member 55, such as a spool.

From the pump line 48 branches off downstream of the pressure compensator 43 each have a control line 56 to one of the 3/2-way proportional pilot pressure control valve 54 a, 54 b, in which an aperture 58 is contained, while from the tank line 47 in each case a control line 57 for Proportional pilot valve branches off, which contains a shutter 59. The pilot valves 54a, 54b have to process only relatively small amounts of control fluid, are small and inexpensive, and need only smaller and less expensive proportional magnets M1, M2 in the execution of Fig. 8 ,

In the de-energized neutral position (as shown in FIG Fig. 9 ) are both working lines 35, 36 relieved to the tank T, and are also the pressure pilot controls 52a, 52b on the proportional pilot valves (Proportional magnet M1, M2 de-energized) to the tank line 47 relieved. The control lines 56 are shut off. These positions of the proportional pilot valves 54a, 54b are adjusted by the springs 42 '.

Will the in Fig. 9 energized to the left proportional solenoid M1 is opened by the control line 56 a pressure-regulating connection via the control line 53b for pilot control 52b, and the spool 50 is pressure controlled so adjusted that pressure fluid in the working line 36 flows to the working port 34 and pressure medium from the working port 33 to the tank T is passed, wherein the pressure in the working line 36 aufsteuert the load-holding valve 38 in the working line 35. The hydraulic cylinder 20 is moved in the selected direction of movement with a current corresponding to the energization of the proportional magnet M1 speed. To change the speed, the current supply is changed. In order to reverse the direction of movement of the hydraulic cylinder 20 and to accurately adjust or vary the speed of movement in the other direction, the other proportional solenoid M2 (in FIG Fig. 9 energized on the right side), so that the pilot valve 54a feeds the pressure control 52a so that the spool 50 is moved via the neutral position to the other control position and pressure fluid flows through the working port 33 and is directed from the working port 34 to the tank. Analogous functions are described in the embodiment in FIG Fig. 8 controlled by the 4/3-way proportional pressure control valve 49 directly actuating proportional magnets M1, M2.

The proportional valve technology can alternatively be used for a screed of a road paver for precise speed adjustment and change, in which the 4/3-way proportional pressure control valve 49 basic screed telescopically and relative to each extendable screed in at least two relative to each other by means of sliding hydraulic cylinders Basic screed has adjustable sections.

Claims (15)

1. Screed (B) for road finishing machines (F), having a basic screed (16) comprising at least one sole plate (21) and at least one extension screed (19) comprising at least one sole plate (22), which extension screed (19) is arranged at the basic screed (16) to be movable relative to the basic screed (16) by means of at least one double actuated hydraulic cylinder (20) for changing the working width (X, X1) of the screed (B), and having an electro-hydraulic control (S, S', 9) comprising at least one magnet-actuated directional control valve at least for controlling the actuation direction of the hydraulic cylinder (20), characterised in that for changing the motion speed of the hydraulic cylinder (20) guided by an operator or automatically depending on at least one road paving mat laying parameter, the directional control valve is a proportional directional control valve (W) with proportional-electric direct actuation or proportional-electric-hydraulic pilot controlled actuation.
2. Screed according to claim 1, characterised in that by means of a proportional magnet (M, M2) of the direct actuation or the pilot controlled actuation of the proportional directional control valve (W), the motion speed of the hydraulic cylinder (20) can be adjusted proportionally to a preferably given motion speed and /or direction of motion of at least one further extension screed component, preferably proportionally to the motion speed and/or an angle (β) of a height and/or lateral inclination drive (23, 23') for the sole plate (22) of the extension screed.
3. Screed according to claim 1, characterised in that the motion speed of the hydraulic cylinder (20) can be changed and maintained load-independently via the proportional directional control valve (W).
4. Screed according to at least one of the preceding claims, characterised in that for the height and/or lateral inclination adjustment of the sole plate (22) of the extension screed relative to the sole plate (21) of the basic screed, hydraulic cylinders and/or spindle drives with hydraulic or electric motors as drives (23, 23') are provided in the extension screed (19) which can be driven at a preferably given motion speed.
5. Screed according to at least one of the preceding claims, characterised in that the proportional directional control valve (W) comprises at least one multi-way multi-position valve in a seat valve or slider valve design.
6. Screed according to at least one of claims 1 to 3, characterised in that the proportional directional control valve (W) comprises at least one two-way or three-way flow regulating valve with a regulating aperture which is adjustable by the proportional magnet (M1, M2).
7. Screed according to at least one of the preceding claims, characterised in that in a control block (29) connected with the electro-hydraulic control (S, S') at least for the respective extension screed moving hydraulic cylinder (20), a 4/3-way proportional pressure regulating valve (49), preferably in a slider valve design having a neutral position open to the tank (T), and equipped with two proportional magnets (M1, M2) acting in opposite directions, is arranged between two work ports (33, 34) of the hydraulic cylinder (20) and a pressure source (P) with an associated tank (T).
8. Screed according to at least one of claims 1 to 6, characterised in that in a control block (29) connected to the electro-hydraulic control (S, S'), two 3/2-way proportion pilot control pressure regulating valves (54a, 54b) with one proportional magnet (M1, M2) each, preferably in a slider valve design, and a 4/3-way pressure regulating valve (51) embodied with hydraulic pilot pressure controls (52a, 52b), preferably in a slider valve design and with a neutral position open to the tank (T), are arranged between two work ports (33, 34) of the hydraulic cylinder (20) and a pressure source (P) with an associated tank (T), wherein each 3/2-way valve (54a, 54b) is connected to one hydraulic pilot pressure control (52a, 52b).
9. Screed according to claim 7 or 8, characterised in that a pressure compensator (43) is associated to the 4/3-way valve (51, 49) on the side of the pressure source, and load holding valves (38) are associated to the 4/3-way valve (51, 49) on the side of the work ports, which load holding valves can be controlled to open crosswise.
10. Screed according to claim 9, characterised in that on the opening control side of the pressure compensator (43), a regulating spring (44) and a load pressure signal preferably picked up by a shuttle valve (41) act on the pressure scale (43), and that supply pressure of the 4/3-way valve (51, 49) acts on the pressure compensator (43) on the closing control side.
11. Screed according to claim 7 or 8, characterised in that at least one work port (34) of the hydraulic cylinder (20) is safeguarded in flow direction to the tank (T) by a pressure limiting valve (37).
12. Screed according to claim 7 or 8, characterised in that the control block (29) comprises, apart from the proportional directional control valves (W) for the hydraulic cylinders (20) for moving the extension screed, also magnet-actuated directional control valves (W') associated to further hydraulic consumers in the screed (B), such as hydraulic cylinders and/or hydraulic motors as drives (23, 23') for height and/or lateral inclination adjustment of the sole plate (22) of the extension screed, and that the control block is connected to a pressure source with associated tank (T) common to all hydraulic consumers, preferably to a hydraulic system (9) of the road finishing machine (F), as well as to a common electro-hydraulic control (S, S').
13. Screed according to at lest one of the preceding claims, characterised in that electric proportional amplifiers are associated to the proportional magnets (M1, M2) of the proportional directional control valve (W).
14. Screed according to at least one of the preceding claims, characterised in that the electro-hydraulic control (S, S') comprises a selectively activated automatic control section (60) for linking the activation of the proportional magnets (M1, M2) with a control of a movement of a further extension screed component.
15. Road finishing machine (F) with a screed (B) comprising extension screeds (19) movable by hydraulic cylinders (20) according to at least one of claims 1 to 14, characterised in that the electro-hydraulic control (S, S') is in actuating connection with proportional magnets (M1, M2) of at least one proportional directional control valve (W) of the screed (B) functionally associated to one hydraulic cylinder (20) each in the screed (B) to adapt the motion speed of the hydraulic cylinder (20) to at least one road paving mat laying parameter.

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