EP0442842B1 - Hydraulic actuator with pressure intensifier - Google Patents

Hydraulic actuator with pressure intensifier Download PDF

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Publication number
EP0442842B1
EP0442842B1 EP91810039A EP91810039A EP0442842B1 EP 0442842 B1 EP0442842 B1 EP 0442842B1 EP 91810039 A EP91810039 A EP 91810039A EP 91810039 A EP91810039 A EP 91810039A EP 0442842 B1 EP0442842 B1 EP 0442842B1
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EP
European Patent Office
Prior art keywords
piston
primary
duct
primary piston
secondary piston
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EP91810039A
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German (de)
French (fr)
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EP0442842A1 (en
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Dionizy Simson
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
    • F15B11/032—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force by means of fluid-pressure converters
    • F15B11/0325—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force by means of fluid-pressure converters the fluid-pressure converter increasing the working force after an approach stroke
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/214—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being hydrotransformers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members

Definitions

  • the present invention relates to a hydraulic cylinder according to the preamble of patent claim 1 and according to the preamble of patent claim 2.
  • Hydraulic cylinders are needed, which generate large forces with small dimensions and weight. Such cylinders are used in piling technology in civil engineering as well as in stamping technology and as clamping elements in machine tools and in robotics.
  • either a shoulder is attached to the circumference of the primary piston or the cylinder tube has a step, or a ring is arranged inside the cylinder tube, which has the advantage that supply bores are not run over by seals and are thereby destroyed.
  • a cylinder 1 is closed on the one hand with a piston rod guide flange 2 and on the other hand with a cylinder base 3.
  • a primary piston 4 is provided with two bores 5 and 6, into which two plungers 7 and 8 penetrate.
  • the holes 5 and 6 are provided with seals 9 and 10.
  • the plungers 7 and 8 are rigidly connected to a secondary piston 11 in a ring shape.
  • the secondary piston 11 is on the piston rod 12 of the primary piston 4 and is movably sealed with respect to the cylinder 1 and the piston rod 12 with seals 13 and 14.
  • In the piston rod guide flange 2 there is also a seal 15 for sealing the piston rod 12 from the flange.
  • the primary piston 4 is also provided with a seal 16 at its end remote from the piston rod 12.
  • the primary and secondary pistons are shown in the upper half of FIG. 1 in a first position and in the lower half in a second position.
  • the cylinder base 3 contains two unlockable check valves 17 and 18, the check valve 17 being biased by a strong spring 19 and the check valve 18 by a weak spring 20.
  • the check valves 17 and 18 are unlocked by two unlocking pistons 21 and 22 designed as balls.
  • a supply line 23 for the fluid opens into the two narrower areas 24 and 25 of the check valve chambers 26 and 27.
  • the line 23 opens into the narrow areas 28 and 29, which are located between the check valves 17 and 18 and the release pistons 21 and 22 Parts 24 and 25 of the chambers 26 and 27.
  • a further supply line for the fluid opens at points 31 and 32 into the areas 33 and 34 of the check valve chambers, which are located behind the unlocking pistons, and connects the two chambers.
  • Another line 35 connects the check valve chamber 26 with the space 36 between the secondary piston 11 and the piston rod guide flange 2.
  • Another line 37 connects the part 34 of the check valve chamber 27 with a junction 38 in the cylinder barrel.
  • Another line 39 connects the check valve chamber 27 to the space 40, which is located between the cylinder base 3 and the primary piston 4.
  • bores 41 and 42 which connect the front to the rear of the valves.
  • Both pistons 4 and 11 are in their initial positions, as shown in the upper half of FIG. 1.
  • the check valve 18 opens with the weak spring 20, and thus the pressure fluid can flow through the bore 42 and the line 39 into the chamber 40.
  • the primary piston 4 moves until it encounters hard resistance.
  • the flow of the pressure fluid is interrupted for a short time, the check valve 18 closes with the weak spring 20 and the check valve 17 with the strong spring 19 is opened by the pressure building up.
  • the pressure fluid flows via the line 35 into the chamber 36, which has the consequence that the secondary piston 11 begins to move and the plungers 7 and 8 penetrate into the bores 5 and 6 of the primary piston 4.
  • the ratio between the pressurized areas of the secondary piston 11 and the plungers 7 and 8 are dimensioned in such a way that a hydraulic transmission occurs.
  • the pressure of the pressure fluid in the chamber 40 increases in accordance with the hydraulic translation.
  • the primary piston 4 moves forward with increased force until the resistance reaches the same size as the force generated. In this case, both the primary piston 4 and the secondary piston 11 do not reach their end position.
  • the pressure in the supply line is equalized, the check valve 17 closes, and the inflow of the hydraulic fluid can be interrupted. The pressure reached is retained.
  • the pressure in the line 30 is increased, the unlocking pistons 21 and 22 unlocking the two check valves 17 and 18.
  • the pressure fluid flows through the line 37 into the chamber 45 and forces the primary piston 4 and the secondary piston 11 back into their starting positions.
  • the pressure fluid can escape from the chambers 36 and 40 without pressure via the lines 35, 39 and 23.
  • the primary piston 4 does not encounter any fixed resistance in its forward movement, it comes to a stop with the secondary piston 11, in which case the latter cannot move and the pressure increase is not initiated. In this case, only the primary force acts on the piston rod guide flange 2 and the same cannot be torn off.
  • the shoulder 43 on the primary piston 4 or on the secondary piston 11 ensures that the mouth 38 of the line 37 is not is covered by a seal, and that through the shoulder 43 a hydraulic connection with the chamber 45 is constantly maintained. If the primary piston 4 encounters a resilient resistance during its forward movement, the translation process is initiated, but the maximum force is not reached because the secondary piston 11, after executing its stroke with the plungers 7 and 8, comes into contact with the cylinder base 3. The mouth 38 of the line 37 is not run over, and the seals are not destroyed. This situation is shown in the lower part of FIG. 1.
  • the cylinder tube 46 has a gradation 47, as a result of which a fixed stop 48 is formed for the primary piston.
  • the stop for the primary piston is formed by a split ring 49 within the cylinder tube 50, which ring is spread by a spring ring 51.
  • the solutions according to FIGS. 2 and 3 are less advantageous than those according to FIG. 1, since the translated force nevertheless arises when the stroke is carried out and then has to be absorbed with considerable effort. Also in the embodiments according to FIGS. 2 and 3, different positions of the pistons are shown in the drawing in the upper and lower halves. 2 and 3 is the same as that in FIG. 1.
  • the primary piston 52 has no axial bores and the secondary piston 53 has no plungers.
  • the primary piston is designed in three stages and has an axial line 54, which connects the chamber 55 to the chamber 56.
  • the secondary piston 53 has a two-stage bore 57, which is provided with seals 58, 59 at both ends.
  • a step 61 on the secondary piston ensures that there is always a hydraulic connection between the line mouth 62 and the chamber 63.
  • the function is the same as in the embodiment according to FIG. 1, ie when the primary piston 53 is maximally extended, a hydraulic transmission cannot occur at all. 4, different positions of the pistons are shown in the drawing in the upper and lower half.
  • the exemplary embodiments according to FIGS. 1 and 4 make it impossible to generate high internal forces which have to be absorbed afterwards.
  • the possibility of using commercially available stepless cylinder tubes in the exemplary embodiments according to FIGS. 1, 3 and 4 allows the manufacturing costs to be reduced considerably.
  • the check valves in the cylinder bottom By placing the check valves in the cylinder bottom, the high pressure area is limited to only one room and its size is only determined by the stroke of the primary piston.
  • the cylinder tube can be tapered, which is particularly desirable when used as a clamping cylinder in civil engineering, since the clamping body can then be made more solid.
  • the embodiment according to FIG. 4 is suitable especially for cylinders with small diameters for robotics.

Abstract

The hydraulic actuator has a cylinder tube (1), a piston-rod guide flange (2) and a cylinder base (1). A primary piston (4) provided with a piston rod (6) is arranged inside the actuator. Furthermore, a secondary piston (11) connected to two plungers (7, 8) is arranged inside the actuator. The plungers plunge into two bores (5, 6) of the primary piston. Two unlockable non-return valves (17, 18) preloaded by springs (19, 20) are provided in the cylinder base. Located in the non-return valves is one bore (41, 42) each, which connects the front side to the rear side of the respective valve. The rear parts (24, 25) of the valve chambers (26, 27) each have an unlocking piston (21, 22) designed as a ball. Two feed lines (23, 30) for the hydraulic fluid are connected to the non-return valve chambers, these chambers in turn having feed lines at various points of the inner space (16, 40, 45) of the actuator. A very compact type of construction can be made possible for the hydraulic actuator with pressure intensifier.

Description

Die vorliegende Erfindung bezieht sich auf einen Hydraulikzylinder gemäss dem Oberbegriff des Patentanspruch 1 sowie gemäss dem Oberbegriff des Patentanspruch 2.The present invention relates to a hydraulic cylinder according to the preamble of patent claim 1 and according to the preamble of patent claim 2.

Es werden Hydraulikzylinder gebraucht, welche grosse Kräfte bei kleinen Abmessungen und Gewicht erzeugen. Solche Zylinder finden in der Rammtechnik im Tiefbau sowie in der Stanztechnik und als Spannelemente in Werkzeugmaschinen und in der Robotik Anwendung.Hydraulic cylinders are needed, which generate large forces with small dimensions and weight. Such cylinders are used in piling technology in civil engineering as well as in stamping technology and as clamping elements in machine tools and in robotics.

Bekannte Lösungen, z.B. gemäss der EP-0 164 334, müssen ein innen abgestuftes Zylinderrohr aufweisen. Im weiteren sind die Ventile bei diesem bekannten hydraulischen Zylinder seitlich angeordnet. Diese Bauweise vergrössert den Zylinder beträchtlich und verursacht auch entsprechende Herstellungskosten. Eine Betätigung eines solchen Zylinders im Falle, wo ein fester Anschlag fehlt, führt zu dessen Beschädigung, da der Führungsflansch der Kolbenstange abgerissen wird.Known solutions, e.g. According to EP-0 164 334, an internally stepped cylinder tube must have. Furthermore, the valves in this known hydraulic cylinder are arranged laterally. This design increases the size of the cylinder considerably and also causes corresponding manufacturing costs. Actuation of such a cylinder in the case where a fixed stop is missing leads to its damage since the guide flange of the piston rod is torn off.

Es ist eine Aufgabe der vorliegenden Erfindung, einen Hydraulikzylinder mit Druckübersetzung derart auszubilden, dass die obgenannten Nachteile vermieden werden, wobei eine sehr kompakte Bauweise für den Hydraulikzylinder mit Druckübersetzung ermöglicht werden soll.It is an object of the present invention to design a hydraulic cylinder with pressure transmission in such a way that the abovementioned disadvantages are avoided, a very compact design for the hydraulic cylinder with pressure transmission being made possible.

Dies wird erfindungsgemäss erzielt durch die kennzeichnenden Merkmale des Patentanspruches 1.According to the invention, this is achieved by the characterizing features of patent claim 1.

Es ist eine weitere Aufgabe der vorliegenden Erfindung, einen Hydraulikzylinder mit Druckübersetzung derart auszubilden, dass ein Zylinder ohne Abstufungen verwendet werden kann, was zu einer beträchtlichen Verbilligung führt. Dies wird erfindungsgemäss erzielt durch die kennzeichnenden Merkmale des Patentanspruches 2.It is a further object of the present invention to design a hydraulic cylinder with pressure transmission in such a way that a cylinder without gradations can be used, which leads to a considerable reduction in price. According to the invention, this is achieved by the characterizing features of patent claim 2.

Da die Kolbenstange des Primärkolbens den Sekundärkolben durchdringt, und im Falle der Bauweise mit Plunger dieselben wiederum den Primärkolben durchdringen, bedarf es eines Minimums an Länge.Since the piston rod of the primary piston penetrates the secondary piston and, in the case of the design with a plunger, they in turn penetrate the primary piston, a minimum length is required.

Bei bevorzugten Ausführungsbeispielen ist entweder am Umfang des Primärkolbens ein Absatz angebracht oder das Zylinderrohr weist eine Abstufung auf, oder es ist innerhalb des Zylinderrohres ein Ring angeordnet, was den Vorteil aufweist, dass Zuleitungsbohrungen nicht durch Dichtungen überfahren werden und dabei einer Zerstörung unterliegen.In preferred exemplary embodiments, either a shoulder is attached to the circumference of the primary piston or the cylinder tube has a step, or a ring is arranged inside the cylinder tube, which has the advantage that supply bores are not run over by seals and are thereby destroyed.

Bevorzugte Ausführungsformen ergeben sich aus den abhängigen Patantansprüchen.Preferred embodiments result from the dependent claims.

Im folgenden werden anhand der beiliegenden Zeichnung Ausführungsbeispiele der Erfindung näher beschrieben. Es zeigen:

Fig. 1
ein erstes Ausführungsbeispiel eines Hydraulikzylinders mit Druckübersetzung,
Fig. 2
ein zweites Ausführungsbeispiel der Erfindung,
Fig. 3
ein drittes Ausführungsbeispiel der Erfindung,
Fig. 4
ein viertes Ausführugnsbeispiel der Erfindung.
Exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings. Show it:
Fig. 1
a first embodiment of a hydraulic cylinder with pressure transmission,
Fig. 2
a second embodiment of the invention,
Fig. 3
a third embodiment of the invention,
Fig. 4
a fourth exemplary embodiment of the invention.

Gemäss Fig. 1 ist ein Zylinder 1 einerseits mit einem Kolbenstangen-Führungsflansch 2 und andererseits mit einem Zylinderboden 3 verschlossen. Ein Primärkolben 4 ist mit zwei Bohrungen 5 und 6 versehen, in welche zwei Plunger 7 und 8 eindringen. Die Bohrungen 5 und 6 sind mit Dichtungen 9 und 10 versehen. Die Plunger 7 und 8 sind mit einem Sekundärkolben 11 in Ringform steif verbunden. Der Sekundärkolben 11 wird auf der Kolbenstange 12 des Primärkolbens 4 geführt und ist gegenüber dem Zylinder 1 und der Kolbenstange 12 mit Dichtungen 13 und 14 beweglich abgedichtet. Im Kolbenstangen-Führungsflansch 2 befindet sich ebenfalls eine Dichtung 15 zur Abdichtung der Kolbenstange 12 gegenüber dem Flansch. Der Primärkolben 4 ist an seinem von der Kolbenstange 12 entfernten Ende ebenfalls mit einer Dichtung 16 versehen. Der Primär- und der Sekundärkolben sind in der oberen Hälfte der Fig. 1 in einer ersten Stellung und in der untern Hälfte in einer zweiten Stellung dargestellt. Der Zylinderboden 3 beinhaltet zwei entsperrbare Rückschlagventile 17 und 18, wobei das Rückschlagventil 17 durch eine starke Feder 19 und das Rückschlagventil 18 durch eine schwache Feder 20 vorgespannt sind. Die Rückschlagventile 17 und 18 werden durch zwei als Kugeln ausgebildete Entsperrkolben 21 und 22 entsperrt. Eine Zuführleitung 23 für das Fluid mündet in die beiden schmäleren Bereiche 24 und 25 der Rückschlagventilkammern 26 und 27. Die Leitung 23 mündet an Stellen 28 und 29, welche sich zwischen den Rückschlagventilen 17 und 18 und den Entsperrkolben 21 und 22 befinden, in die schmalen Teile 24 und 25 der Kammern 26 und 27 ein. Eine weitere Zuführleitung für das Fluid mündet an Stellen 31 und 32 in die Bereiche 33 und 34 der Rückschlaglventilkammern, welche sich hinter den Entsperrkolben befinden, ein und verbindet die beiden Kammern. Eine weitere Leitung 35 verbindet die Rückschlagventilkammer 26 mit dem Raum 36 zwischen dem Sekundärkolben 11 und dem Kolbenstangen-Führungsflansch 2. Eine weitere Leitung 37 verbindet den Teil 34 der Rückschlagventilkammer 27 mit einer Einmündungsstelle 38 in das Zylinderrohr. Eine weitere Leitung 39 verbindet die Rückschlagventilkammer 27 mit dem Raum 40, welcher sich zwischen dem Zylinderboden 3 und dem Primärkolben 4 befindet. In den Rückschlagventilen 17 und 18 befinden sich Bohrungen 41 und 42, welche die Vorderseite mit der Hinterseite der Ventile verbinden. Am Primärkolben 4 oder am Sekundärkolben 11 oder an beiden zugleich befindet sich ein Absatz 43, so dass sich ein Spalt zwischen der Mantelfläche des Primärkolbens und/oder Sekundärkolbens und dem Zylinderrohr bildet.1, a cylinder 1 is closed on the one hand with a piston rod guide flange 2 and on the other hand with a cylinder base 3. A primary piston 4 is provided with two bores 5 and 6, into which two plungers 7 and 8 penetrate. The holes 5 and 6 are provided with seals 9 and 10. The plungers 7 and 8 are rigidly connected to a secondary piston 11 in a ring shape. The secondary piston 11 is on the piston rod 12 of the primary piston 4 and is movably sealed with respect to the cylinder 1 and the piston rod 12 with seals 13 and 14. In the piston rod guide flange 2 there is also a seal 15 for sealing the piston rod 12 from the flange. The primary piston 4 is also provided with a seal 16 at its end remote from the piston rod 12. The primary and secondary pistons are shown in the upper half of FIG. 1 in a first position and in the lower half in a second position. The cylinder base 3 contains two unlockable check valves 17 and 18, the check valve 17 being biased by a strong spring 19 and the check valve 18 by a weak spring 20. The check valves 17 and 18 are unlocked by two unlocking pistons 21 and 22 designed as balls. A supply line 23 for the fluid opens into the two narrower areas 24 and 25 of the check valve chambers 26 and 27. The line 23 opens into the narrow areas 28 and 29, which are located between the check valves 17 and 18 and the release pistons 21 and 22 Parts 24 and 25 of the chambers 26 and 27. A further supply line for the fluid opens at points 31 and 32 into the areas 33 and 34 of the check valve chambers, which are located behind the unlocking pistons, and connects the two chambers. Another line 35 connects the check valve chamber 26 with the space 36 between the secondary piston 11 and the piston rod guide flange 2. Another line 37 connects the part 34 of the check valve chamber 27 with a junction 38 in the cylinder barrel. Another line 39 connects the check valve chamber 27 to the space 40, which is located between the cylinder base 3 and the primary piston 4. In the check valves 17 and 18 there are bores 41 and 42 which connect the front to the rear of the valves. There is a shoulder 43 on the primary piston 4 or on the secondary piston 11 or on both at the same time, so that a gap is formed between the outer surface of the primary piston and / or the secondary piston and the cylinder tube.

Im folgenden soll die Funktionsweise des Hydraulikzylinders gemäss Fig. 1 näher erläutert werden. Beide Kolben 4 und 11 befinden sich in ihren Ausgangslagen, wie in der oberen Hälfte der Fig. 1 abgebildet. Sobald der hydraulische Druck in der Leitung 23 zu wachsen beginnt, öffnet das Rückschlagventil 18 mit der schwachen Feder 20, und somit kann die Druckflüssigkeit durch die Bohrung 42 und die Leitung 39 in die Kammer 40 fliessen. Der Primärkolben 4 bewegt sich solange, bis er auf einen harten Widerstand trifft. Der Durchfluss der Druckflüssigkeit wird für kurze Zeit unterbrochen, wobei sich das Rückschlagventil 18 mit der schwachen Feder 20 schliesst und durch den sich aufbauenden Druck das Rückschlagventil 17 mit der starken Feder 19 geöffnet wird. Die Druckflüssigkeit fliesst über die Leitung 35 in die Kammer 36, was zur Folge hat, dass sich der Sekundärkolben 11 zu bewegen beginnt, und die Plunger 7 und 8 in die Bohrungen 5 und 6 des Primärkolbens 4 eindringen. Das Verhältnis zwischen den druckbeaufschlagten Flächen des Sekundärkolbens 11 und der Plunger 7 und 8 ist so bemessen, dass eine hydraulische Uebersetzung entsteht. Infolge des Eindringens der Plunger 7 und 8 in die Bohrungen 5 und 6 erhöht sich der Druck der Druckflüssigkeit in der Kammer 40 gemäss der hydraulischen Uebersetzung. Der Primärkolben 4 bewegt sich mit erhöhter Kraft solange vorwärts, bis der Widerstand die gleiche Grösse erreicht wie die erzeugte Kraft. In diesem Falle erreicht sowohl der Primärkolben 4 als auch der Sekundärkolben 11 seine Endlage nicht. Der Druck gleicht sich in der Zuleitung aus, das Rückschlagventil 17 schliesst, und der Zufluss der Hydraulikflüssigkeit kann unterbrochen werden. Der erreichte Druck bleibt erhalten.The operation of the hydraulic cylinder according to FIG. 1 will be explained in more detail below. Both pistons 4 and 11 are in their initial positions, as shown in the upper half of FIG. 1. As soon as the hydraulic pressure in line 23 begins to increase, the check valve 18 opens with the weak spring 20, and thus the pressure fluid can flow through the bore 42 and the line 39 into the chamber 40. The primary piston 4 moves until it encounters hard resistance. The flow of the pressure fluid is interrupted for a short time, the check valve 18 closes with the weak spring 20 and the check valve 17 with the strong spring 19 is opened by the pressure building up. The pressure fluid flows via the line 35 into the chamber 36, which has the consequence that the secondary piston 11 begins to move and the plungers 7 and 8 penetrate into the bores 5 and 6 of the primary piston 4. The ratio between the pressurized areas of the secondary piston 11 and the plungers 7 and 8 are dimensioned in such a way that a hydraulic transmission occurs. As a result of the penetration of the plungers 7 and 8 into the bores 5 and 6, the pressure of the pressure fluid in the chamber 40 increases in accordance with the hydraulic translation. The primary piston 4 moves forward with increased force until the resistance reaches the same size as the force generated. In this case, both the primary piston 4 and the secondary piston 11 do not reach their end position. The pressure in the supply line is equalized, the check valve 17 closes, and the inflow of the hydraulic fluid can be interrupted. The pressure reached is retained.

Um beide Kolben in die Ausgangslage zu bringen, wird der Druck in der Leitung 30 erhöht, wobei die Entsperrkolben 21 und 22 die beiden Rückschlagventile 17 und 18 entsperren. Dabei fliesst die Druckflüssigkeit über die Leitung 37 in die Kammer 45 und drängt den Primärkolben 4 und den Sekundärkolben 11 in ihre Ausgangslagen zurück. Die Druckflüssigkeit kann aus den Kammern 36 und 40 über die Leitungen 35, 39 und 23 drucklos entweichen.In order to bring both pistons into the starting position, the pressure in the line 30 is increased, the unlocking pistons 21 and 22 unlocking the two check valves 17 and 18. The pressure fluid flows through the line 37 into the chamber 45 and forces the primary piston 4 and the secondary piston 11 back into their starting positions. The pressure fluid can escape from the chambers 36 and 40 without pressure via the lines 35, 39 and 23.

Falls der Primärkolben 4 in seiner Vorwärtsbewegung auf keinen festen Widerstand stösst, kommt er zum Anschlag mit dem Sekundärkolben 11, wobei dieser dann keine Bewegung ausführen kann, und die Druckerhöhung nicht eingeleitet wird. Auf den Kolbenstangen-Führungsflansch 2 wirkt in diesem Falle nur die Primärkraft, und derselbe kann nicht abgerissen werden. Der Absatz 43 am Primärkolben 4 oder am Sekundärkolben 11 sorgt dafür, dass die Mündung 38 der Leitung 37 nicht durch eine Dichtung überdeckt wird, und dass durch den Absatz 43 ständig eine hydraulische Verbindung mit der Kammer 45 aufrechterhalten wird. Trifft der Primärkolben 4 während seiner Vorwärtsbewegung auf einen nachgiebigen Widerstand, erfolgt eine Einleitung des Uebersetzungsvorganges, die maximale Kraft wird jedoch nicht erreicht, da der Sekundärkolben 11 nach Ausführen seines Hubes mit den Plungern 7 und 8 mit dem Zylinderboden 3 in Anschlag kommt. Dabei werden auch die Mündung 38 der Leitung 37 nicht überfahren, und die Dichtungen nicht zerstört. Diese Lage ist im unteren Teil der Fig. 1 abgebildet.If the primary piston 4 does not encounter any fixed resistance in its forward movement, it comes to a stop with the secondary piston 11, in which case the latter cannot move and the pressure increase is not initiated. In this case, only the primary force acts on the piston rod guide flange 2 and the same cannot be torn off. The shoulder 43 on the primary piston 4 or on the secondary piston 11 ensures that the mouth 38 of the line 37 is not is covered by a seal, and that through the shoulder 43 a hydraulic connection with the chamber 45 is constantly maintained. If the primary piston 4 encounters a resilient resistance during its forward movement, the translation process is initiated, but the maximum force is not reached because the secondary piston 11, after executing its stroke with the plungers 7 and 8, comes into contact with the cylinder base 3. The mouth 38 of the line 37 is not run over, and the seals are not destroyed. This situation is shown in the lower part of FIG. 1.

Beim Ausführungsbeispiel gemäss Fig. 2 weist das Zylinderrohr 46 eine Abstufung 47 auf, wodurch ein fester Anschlag 48 für den Primärkolben gebildet wird.In the exemplary embodiment according to FIG. 2, the cylinder tube 46 has a gradation 47, as a result of which a fixed stop 48 is formed for the primary piston.

Beim Ausführungsbeispiel gemäss Fig. 3 wird der Anschlag für den Primärkolben durch einen geteilten Ring 49 innerhalb des Zylinderrohres 50 gebildet, welcher Ring durch einen Federring 51 gespreizt wird. Die Lösungen gemäss den Fig. 2 und 3 sind weniger vorteilhaft als diejenige gemäss Fig. 1, da die übersetzte Kraft beim Ausführen des Hubes doch entsteht und dann mit beträchtlichem Aufwand aufgefangen werden muss. Auch bei den Ausführungsformen gemäss den Fig. 2 und 3 sind in der Zeichnung jeweils in der oberen und unteren Hälfte verschiedene Stellungen der Kolben dargestellt. Die Funktionsweise der Ausführungsbeispiele gemäss der Fig. 2 und 3 ist dieselbe wie bei derjenigen gemäss Fig. 1.3, the stop for the primary piston is formed by a split ring 49 within the cylinder tube 50, which ring is spread by a spring ring 51. The solutions according to FIGS. 2 and 3 are less advantageous than those according to FIG. 1, since the translated force nevertheless arises when the stroke is carried out and then has to be absorbed with considerable effort. Also in the embodiments according to FIGS. 2 and 3, different positions of the pistons are shown in the drawing in the upper and lower halves. 2 and 3 is the same as that in FIG. 1.

Beim Ausführungsbeispiel gemäss Fig. 4 besitzt der Primärkolben 52 keine axialen Bohrungen und der Sekundärkolben 53 weist keine Plunger auf. Bei diesem Ausführungsbeispiel ist der Primärkolben dreistufig ausgebildet und weist eine axiale Leitung 54 auf, welche die Kammer 55 mit der Kammer 56 verbindet. Der Sekundärkolben 53 weist eine zweistufige Bohrung 57 auf, welche an beiden Enden mit Dichtungen 58, 59 versehen ist. Eine Abstufung 61 am Sekundärkolben sorgt dafür, dass zwischen der Leitungsmündung 62 und der Kammer 63 ständig eine hydraulische Verbindung besteht. Die Funktion ist die gleiche wie bei der Ausführungsform gemäss der Fig. 1, d.h. bei maximalem Ausfahren des Primärkolbens 53 kann eine hydraulische Uebersetzung gar nicht entstehen. Auch beim Ausführungsbeispiel gemäss Fig. 4 sind in der Zeichnung in der oberen und unteren Hälfte verschiedene Stellungen der Kolben dargestellt.4, the primary piston 52 has no axial bores and the secondary piston 53 has no plungers. In this exemplary embodiment, the primary piston is designed in three stages and has an axial line 54, which connects the chamber 55 to the chamber 56. The secondary piston 53 has a two-stage bore 57, which is provided with seals 58, 59 at both ends. A step 61 on the secondary piston ensures that there is always a hydraulic connection between the line mouth 62 and the chamber 63. The function is the same as in the embodiment according to FIG. 1, ie when the primary piston 53 is maximally extended, a hydraulic transmission cannot occur at all. 4, different positions of the pistons are shown in the drawing in the upper and lower half.

Die Ausführungsbeispiele gemäss den Fig. 1 und 4 verunmöglichen eine Entstehung hoher interner Kräfte, welche im nachhinein aufgefangen werden müssen. Die Möglichkeit, handelsübliche stufenlose Zylinderrohre bei den Ausführungsbeispielen gemäss den Fig. 1, 3 und 4 zu verwenden, erlaubt, die Herstellungskosten beträchtlich zu senken. Durch das Anordnen der Rückschlagventile im Zylinderboden wird der Hochdruckbereich auf nur einen Raum begrenzt, und seine Grösse wird nur durch den Hub des Primärkolbens bestimmt. Im Niederdruckteil, im Bereich des Sekundärkolbens, kann das Zylinderrohr verjüngt werden, was vor allem bei der Anwendung als Klemmzylinder im Tiefbau erwünscht ist, da der Klemmkörper dann massiver ausgebildet sein kann. Das Ausführungsbeispiel gemäss der Fig. 4 eignet sich vorzüglich für Zylinder mit kleinen Durchmessern für die Robotik.The exemplary embodiments according to FIGS. 1 and 4 make it impossible to generate high internal forces which have to be absorbed afterwards. The possibility of using commercially available stepless cylinder tubes in the exemplary embodiments according to FIGS. 1, 3 and 4 allows the manufacturing costs to be reduced considerably. By placing the check valves in the cylinder bottom, the high pressure area is limited to only one room and its size is only determined by the stroke of the primary piston. In the low-pressure part, in the area of the secondary piston, the cylinder tube can be tapered, which is particularly desirable when used as a clamping cylinder in civil engineering, since the clamping body can then be made more solid. The embodiment according to FIG. 4 is suitable especially for cylinders with small diameters for robotics.

Claims (4)

  1. Hydraulic cylinder with pressure transmission with a cylinder jacket (1), a piston-rod guide flange (2), a cylinder bottom (3), a primary piston (4) provided with a piston rod (12), and a secondary piston (11), the primary piston (4) and the secondary piston (11) being disposed axially one behind the other and movably toward one another, and the secondary piston being disposed between the primary piston and the guide flange, and two openable check valves (17, 18), biased by two springs (19, 20), being disposed in said cylinder bottom (3), the elasticity constants of the two springs (19, 20) being different, and the chamber (26) of the one check valve (17) being connected by a first duct (35) to the space (36) located between the piston-rod guide flange (2) and the secondary piston (11), and the chamber (27) of the other check valve (18) being connected by a second duct (39) to the space (40) located between the cylinder bottom (3) and the primary piston (4), the rear portions (24, 25) of the two chambers (26, 27) each having an unstopping piston (21, 22), and the rear portions being connected with each other by a third duct (37), which third duct opens into the space (44) between the primary piston (4) and the secondary piston (11), characterized in that the primary piston (4) is provided with at least two bores (5, 6) into which penetrate at least two plungers (7, 8) connected to the secondary piston (11) and the ratio between the pressure-impinged areas of the secondary piston and the plungers is such that a hydraulic pressure transmission occurs.
  2. Hydraulic cylinder with pressure transmission with a cylinder jacket (1), a piston-rod guide flange (2), a cylinder bottom (3), a primary piston (52) provided with a piston rod (12), and a secondary piston (53), the primary piston (52) and the secondary piston (53) being disposed axially one behind the other and movably toward one another, and the secondary piston being disposed between the primary piston and the guide flange, and two openable check valves (17, 18), biased by two springs (19, 20), being disposed in said cylinder bottom (3), the elasticity constants of the two springs (19, 20) being different, and the chamber (26) of the one check valve (17) being connected by a first duct (35) to the space (36) located between the piston-rod guide flange (2) and the secondary piston (53), and the chamber (27) of the other check valve (18) being connected by a second duct (39) to the space (55) located between the cylinder bottom (3) and the primary piston (4) <sic. 52>, the rear portions (24, 25) of the two chambers (26, 27) each having an unstopping piston (21, 22), and the rear portions being connected with each other by a third duct (37), which third duct opens into the space (63) between the primary piston (52) and the secondary piston (53) characterized in that the secondary piston (53) is provided with a two-stepped axial bore (57) which has gaskets (58, 59) on both ends, and a chamber (56) is formed between the inner frontal face of the multistepped primary piston (52) and the axial bore (57) of the secondary piston (53), and the primary piston (52) is traversed by an axial duct (54), which duct connects the chamber (56) and the space (55).
  3. Hydraulic cylinder according to claim 1, characterized in that there is a shoulder (43) provided on the circumference of the primary piston (4).
  4. Hydraulic cylinder according to one of the preceding claims, characterized in that there is a bore (41, 42) provided on each of the check valves (17, 18), which bore connects the front and rear sides of the valve (17, 18).
EP91810039A 1990-02-14 1991-01-17 Hydraulic actuator with pressure intensifier Expired - Lifetime EP0442842B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT91810039T ATE104023T1 (en) 1990-02-14 1991-01-17 HYDRAULIC CYLINDERS WITH PRESSURE INCREASE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH47690 1990-02-14
CH476/90 1990-02-14

Publications (2)

Publication Number Publication Date
EP0442842A1 EP0442842A1 (en) 1991-08-21
EP0442842B1 true EP0442842B1 (en) 1994-04-06

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ID=4187877

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EP91810039A Expired - Lifetime EP0442842B1 (en) 1990-02-14 1991-01-17 Hydraulic actuator with pressure intensifier

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EP (1) EP0442842B1 (en)
JP (1) JPH051703A (en)
AT (1) ATE104023T1 (en)
DE (1) DE59101302D1 (en)
PL (1) PL165086B1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06342623A (en) * 1993-06-01 1994-12-13 S O C Kk Chip fuse
DE102006029523B4 (en) * 2006-06-27 2014-10-23 Damcos A/S locking device
CN108561446B (en) * 2018-01-18 2024-03-15 申科滑动轴承股份有限公司 Hydraulic locking device for thrust head

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1296522B (en) * 1958-05-22 1969-05-29 Glas Maurus Hydraulic pressure unit with pressure transmission
US3410089A (en) * 1967-03-08 1968-11-12 Joseph D. Snitgen Fluid operated device
CH665007A5 (en) * 1984-05-11 1988-04-15 Enfo Grundlagen Forschungs Ag HYDRAULIC CYLINDER WITH POWER MULTIPLICATION.

Also Published As

Publication number Publication date
PL288948A1 (en) 1992-01-27
PL165086B1 (en) 1994-11-30
ATE104023T1 (en) 1994-04-15
EP0442842A1 (en) 1991-08-21
DE59101302D1 (en) 1994-05-11
JPH051703A (en) 1993-01-08

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