Hydraulic cylinder assembly and method for operating a hydraulic cylinder assembly

Abstract

Hydraulic cylinder arrangement (1), comprising at least a hydraulic cylinder (2), a motor (3) for driving an adjustable pump (4), the pump (4), and a swivel angle control system (5) for the pump (4), wherein the swivel angle control system (5) comprises at least one actuating piston (6) for adjusting the pump (4) and an electrically controlled valve (7) for controlling the actuating piston (6); wherein at least one delivery direction of the pump (4) and thus a movement of the hydraulic cylinder (2) can be controlled via the swivel angle control system (5); wherein the hydraulic cylinder arrangement (1) comprises an electrical control unit (8) for operating at least the motor (3) and the valve (7);characterized in that the hydraulic cylinder arrangement (1) has an uninterruptible power supply (9) so that, in the event of a power supply failure (10) for the control unit (8), at least the control unit (8) can be supplied with electrical energy by the uninterruptible power supply (9). Method for operating a hydraulic cylinder arrangement.

Description

[0001] The invention relates to a hydraulic cylinder arrangement and a method for operating a hydraulic cylinder arrangement. A hydraulic cylinder is adjustable, in particular, between at least two (extreme) positions. A piston is displaced within the cylinder. A hydraulic medium is supplied to the cylinder to displace the piston. The medium is pumped by a pump, which can be driven, for example, by an electric motor. To move the piston back and forth, the cylinder can, for example, comprise two chambers which can be pressurized with the medium depending on the desired position of the piston.

[0002] It is known that in hydraulic cylinder arrangements, for example, residual movement of the piston can be prevented after the hydraulic cylinder arrangement has been switched off. This can be achieved, for example, by using shut-off valves that interrupt the hydraulic connection between a chamber or chambers of the cylinder and the pump. The motor intended to drive the pump is thereby switched off, in particular without torque.

[0003] Switching to a torque-free state (in which the motor provides no torque for driving or braking) is called "safe-torque-off" (STO).

[0004] Such a shutdown of the hydraulic cylinder arrangement can be triggered by various events: An emergency stop of the hydraulic cylinder assembly is activated; a fault exists or is detected in the system; power failure.

[0005] If, for example, no shut-off valves are provided, the piston will continue to move in line with the pump's delivery rate. Simply triggering a start-stop (STO) on the motor will only bring the pump to a standstill once the kinetic energy of the motor and pump has dissipated (provided no external hydraulic forces are acting on the pump). The pump delivers fluid according to its direction of rotation and, if applicable, its oscillation angle.

[0006] Hydraulic cylinder arrangements with a swivel angle control system are also known. The hydraulic cylinder arrangement then comprises a hydraulic cylinder (with piston), a motor for driving an adjustable pump, the pump itself, and a swivel angle control system for the pump. The swivel angle control system includes at least one actuating piston for adjusting the pump and an electrically controlled valve for regulating the actuating piston. At least one pumping direction, and thus a movement of the hydraulic cylinder or piston, can be controlled via the swivel angle control system. The pump is adjustable via the swivel angle control system between -100% (maximum pumping rate in a first direction), zero% (no pumping of any medium), and +100% (maximum pumping rate in a second direction).

[0007] If the (swivel angle control) valve is switched to its de-energized basic position analogous to the STO of the motor, the swivel angle set at the pump, and thus whether and in which direction the pump delivers, depends on the valve basic position, the valve pressure supply and the presence of springs in the swivel cradle.

[0008] In a so-called A4 HS5 pump with connected control pressure and a de-energized proportional valve or HS5 control valve (as a valve), the minimum pump displacement is, for example, the basic position. This basic position is also reached if the HS5 control valve is de-energized due to a fault (e.g., a broken cable, etc.). In contrast to an open circuit, where the pump pivots to a minimum end stop (zero percent flow rate), in a closed circuit the pump pivots beyond the zero position to -100 percent flow rate (reversal of direction). In this case, the load connected to the pump (e.g., a hydraulic cylinder or hydraulic motor) accelerates maximally in one direction of movement. This behavior can be prevented by implementing a zero-swivel function in the known HS5(E) control system.

[0009] To enable, for example, the pump to swivel to zero% when the swivel control valve is de-energized, especially in pumps with such an unfavorable basic position, an additional (second) valve and an additional (second) piston or cylinder can be provided.

[0010] In normal operation of the hydraulic cylinder assembly, the electrically actuated 4 / 4-way valve, acting as the (first) valve, regulates the pressure conditions in the actuator piston and thus pivots the pump. The first valve is energized and relieves the pressure on the second piston, rendering it ineffective. In the event of a malfunction of the (first) valve, it moves to a default position in which one (first) chamber of the actuator piston is connected to the return line and thus relieved of pressure. The other (second) actuator piston chamber is connected to the control pressure. This causes the actuator piston to move towards the first chamber. To prevent the actuator piston from reaching its end position (where the pump's maximum delivery rate is set), the second valve is deactivated, connecting the second piston / cylinder to the control pressure.This causes the second piston to extend to an adjustable end stop (which corresponds to the center position, i.e., the pump's zero percent position). The effective area of ​​the second piston is larger than the effective area of ​​the actuating piston, ensuring that the end position of the second piston or cylinder is always reached, which again corresponds to the center position, i.e., the pump's zero percent position.

[0011] However, the second piston and the second valve are required to implement this hydraulic cylinder arrangement.

[0012] Based on this, the object of the invention is to at least partially alleviate the problems described with reference to the prior art and, in particular, to provide a more cost-effective solution for a hydraulic cylinder arrangement with which an orderly rapid standstill of the hydraulic cylinder can be achieved.

[0013] These problems are solved by the subject matter of the independent claims. Preferred embodiments are found in the dependent claims. The features specified in the claims can be combined with each other and / or with features of the description in any technologically meaningful way. The description, particularly in conjunction with the figures, explains the invention and provides further embodiments.

[0014] This is achieved through a hydraulic cylinder arrangement comprising at least one hydraulic cylinder, a motor for driving an adjustable pump, the pump itself, and a swivel angle control system for the pump. The swivel angle control system includes at least one actuating piston for adjusting the pump and an electrically controlled valve for regulating the actuating piston. The swivel angle control system allows for the regulation of at least one pump delivery direction (in particular between -100% and +100% delivery rate) and thus the movement of the hydraulic cylinder. The hydraulic cylinder arrangement includes an electrical control unit for operating at least the motor and the valve.

[0015] The hydraulic cylinder arrangement also has an uninterruptible power supply, so that in the event of a power supply failure for the control unit, at least the control unit can be supplied with electrical energy by the uninterruptible power supply.

[0016] In particular, in the event of a power failure for the control unit, at least the valve can be controlled via the energy provided by the uninterruptible power supply in such a way that the pivot angle of the pump can be adjusted to zero % via the actuating piston.

[0017] In particular, if the power supply to the control unit fails, at least the motor can be braked to zero rpm using the energy provided by the uninterruptible power supply, especially via a braking resistor.

[0018] In particular, the uninterruptible power supply comprises a capacitor or an intermediate circuit connected to the power supply, wherein the capacitor or intermediate circuit provides the energy to supply at least the control unit in the event of a power supply failure.

[0019] The capacitor or intermediate circuit is dimensioned in such a way that sufficient electrical energy is stored or can be stored. Sufficient means, in particular, that at least the motor can be braked to zero rpm [revolutions per minute] and / or the valve can be controlled long enough to adjust the pump's oscillation angle to zero percent via the actuating piston.

[0020] An intermediate circuit is, in particular, a generally known electrical device that, as an energy storage device, electrically couples several electrical networks at an intermediate current or voltage level, e.g., via a converter. A capacitor is also generally known as an energy storage device.

[0021] Uninterruptible power supplies designed as modules are also well known.

[0022] In particular, this ensures that the hydraulic cylinder comes to a standstill (pump no longer delivers fluid or is in the zero percent position and / or the motor no longer drives the pump).

[0023] A method for operating a hydraulic cylinder arrangement, in particular the described hydraulic cylinder arrangement, is further proposed. The hydraulic cylinder arrangement comprises at least one hydraulic cylinder, a motor for driving an adjustable pump, the pump itself, and a swivel angle control system for the pump, wherein the swivel angle control system includes at least one actuating piston for adjusting the pump and an electrically controlled valve for controlling the actuating piston. At least one pumping direction, and thus a movement of the hydraulic cylinder, can be controlled via the swivel angle control system. The hydraulic cylinder arrangement includes an electrical control unit for operating at least the motor and the valve, and an uninterruptible power supply (UPS). In the event of a power supply failure, the method comprises at least the following steps: a) Supplying at least the control unit with electrical energy from the uninterruptible power supply; and (thereby) at least b) braking the motor to zero rpm using the energy provided by the uninterruptible power supply or actuating the valve using the energy provided by the uninterruptible power supply, so that the pump's swivel angle is adjusted to zero % via the actuating piston.

[0024] Steps a) and b) are carried out together, in particular, meaning that the braking of the motor (e.g. by a braking resistor - possibly electrically actuated and mechanically acting or exclusively electrically acting) and / or the actuation of the valve is carried out (only) by the electrical energy of the uninterruptible power supply.

[0025] Without the control of the valve, the valve would otherwise move, in particular, to a basic position in which the actuating piston is moved to one of the end positions, so that the pump would then be adjusted to -100% or +100% swivel angle and the hydraulic cylinder would be moved further.

[0026] In particular, step b) completely consumes the energy supplied by the uninterruptible power supply. Specifically, after step b), the hydraulic cylinder assembly is de-energized, meaning that no electrical energy remains in the hydraulic cylinder assembly (i.e., in the control unit, the uninterruptible power supply, or other components).

[0027] The control unit is, in particular, a data processing system that includes means suitable for carrying out the procedure, whether equipped, configured, or programmed to execute the procedure. Specifically, the control unit is supplied with electrical energy by the power supply when a fault occurs. The present procedure involves supplying the control unit with electrical energy via the uninterruptible power supply (UPS) if the power supply fails or is interrupted (e.g., by an emergency stop switch). The initiation of motor braking and / or the described actuation of the valve then takes place via the UPS.

[0028] The means include, for example, a processor and a memory in which instructions to be executed by the processor are stored, as well as data lines or transmission devices that enable the transmission of instructions, measurements, data or the like between the aforementioned elements.

[0029] The "means" may include, in particular, one or more of the following components: control(s), microcontroller, data storage, data connection, display devices (such as a display), counter or timer, at least one additional sensor, a power source (the uninterruptible power supply, which may be integrated with the control unit or implemented separately), etc.

[0030] Furthermore, a computer program is proposed, comprising commands which, when executed by a computer, cause the computer to perform the described procedure or the steps of the described procedure.

[0031] Furthermore, a computer-readable storage medium is proposed, comprising instructions which, when executed by a computer, cause it to perform the described procedure or the steps of the described procedure.

[0032] The explanations regarding the procedure are particularly applicable to the hydraulic cylinder unit, the data processing system and / or the computer-implemented procedure (i.e., the computer program and the computer-readable storage medium) and vice versa.

[0033] The described hydraulic cylinder arrangement and method enable the hydraulic cylinder unit to be brought to a controlled standstill within a short time (provided no external forces are moving it), particularly despite the presence of a swivel angle control system. Without the uninterruptible power supply, the actuating piston, when moved to its home position, would, depending on the pressure supply to the swivel angle control system's valve, either be moved out of its zero position (i.e., zero percent swivel angle) or, for example, be moved only relatively slowly and imprecisely towards the zero position by a spring. Due to the continued power supply from the uninterruptible power supply, the pump motor is not (initially) switched off without torque, but is actively braked to zero rpm. A braking resistor is used, in particular, to brake the motor.

[0034] Due to the provision of an uninterruptible power supply, shut-off valves on the hydraulic cylinder are not required. Furthermore, there are no pressure losses caused by these additional shut-off valves. Additionally, the chambers of the hydraulic cylinder are not isolated (by the shut-off valves), which can sometimes be undesirable. Pressure spikes, which can occur when shut-off valves are suddenly activated, also cannot occur between (any existing) shut-off valves and the pump. Of course, shut-off valves can be provided if necessary or helpful.

[0035] As a result of the provision of an uninterruptible power supply, the special version of the swivel angle control system described at the beginning (with a second valve and a second piston) is also not required.

[0036] In particular, the following events can be solved by the described hydraulic cylinder arrangement or the described method as follows: Event A: Emergency Stop. An emergency stop switch is activated, i.e., the power supply is interrupted. The motor of the hydraulic cylinder assembly is braked to zero rpm as quickly as possible. The pump's swivel angle is adjusted to 0% as quickly as possible. As a result of these measures, the hydraulic cylinder comes to a standstill (as quickly as possible). If necessary, after a waiting period (especially less than one second), the motor is switched to torque-free operation (STO). Event B: Fault. A fault occurs in the hydraulic cylinder assembly (e.g., a component temperature is too high). The motor of the hydraulic cylinder assembly is braked to zero rpm as quickly as possible. The pump's swivel angle is adjusted to 0% as quickly as possible. As a result of these measures, the hydraulic cylinder comes to a standstill (as quickly as possible). Event C: Power Failure. The power supply to the hydraulic cylinder assembly fails.The control unit of the hydraulic cylinder assembly (e.g., an inverter, the valve of the rotary angle control system, a rotary angle position sensor located on the actuator piston and / or the pump) continues to be supplied with power via the uninterruptible power supply (UPS) or a UPS module. The pressure supply for the rotary angle control valve can also be maintained. Alternatively, the pressure supply can be designed to provide sufficient pressure and flow rate for a certain period (e.g., the pressure can be supplied from a reservoir for the pressure medium, which is gradually discharged via a nozzle). The motor of the hydraulic cylinder assembly is braked to zero rpm as quickly as possible. The pump's rotary angle is reduced to 0% as quickly as possible.As a result of these measures, the hydraulic cylinder comes to a standstill (as quickly as possible). Only when the uninterruptible power supply no longer delivers any electrical energy or current is the entire hydraulic cylinder assembly de-energized.

[0037] Depending on the design of the hydraulic cylinder arrangement, it may also be the case that a PLC (a generally known programmable logic controller) is supplied with power via the UPS, and depending on the system design, it may also be the case that the control of the swivel angle control valve is housed in external electronics, which are then also supplied with power via the UPS.

[0038] The UPS described here can alternatively be implemented as an additional 24V power supply, which is powered by the described intermediate circuit. Both power supplies result in an additional redundancy module. As long as the intermediate circuit is charged, 24V [volts] are available.

[0039] The use of indefinite articles ("a", "an", "a" and "one"), particularly in the claims and the description reproducing them, is to be understood as such and not as a numeral. Accordingly, terms or components introduced by these articles are to be understood as appearing at least once and, in particular, as potentially appearing multiple times.

[0040] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described. Where a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or some of the multiple components, but this is not mandatory.

[0041] The invention and its technical context will now be explained in more detail with reference to the figures, without these explanations limiting the invention itself. Unless explicitly excluded below, partial aspects or individual features shown in the figures can also be combined with each other and / or with the features of the claims or the preceding description. Where components in different figures are designated with the same reference numeral, their descriptions apply analogously to all such components, unless explicitly stated otherwise. The figures schematically depict: Fig. 1 a first embodiment of a hydraulic cylinder arrangement according to the state of the art, Fig. 2 a second embodiment of a hydraulic cylinder arrangement according to the state of the art, Fig. 3 a third design variant of a hydraulic cylinder arrangement according to the state of the art, Fig. 4 a fourth embodiment of a hydraulic cylinder arrangement according to the state of the art, Fig. 5 a first design variant of a hydraulic cylinder arrangement and Fig. 6 a second design variant of a hydraulic cylinder arrangement.

[0042] The Fig. 1 shows a first embodiment of a hydraulic cylinder arrangement 1 according to the state of the art

[0043] The hydraulic cylinder assembly 1 comprises a hydraulic cylinder 2, an adjustable pump 4 driven by a motor 3, and two shut-off valves 14. This prevents any (residual) movement of the piston of the hydraulic cylinder 2 after the hydraulic cylinder assembly 1 has been switched off. The shut-off valves 14 interrupt the hydraulic connection between the two chambers of the hydraulic cylinder 2 and the pump 4. The motor 3, which drives the pump 4, is thereby de-energized.

[0044] Fig. 2 Figure 1 shows a second embodiment of a hydraulic cylinder arrangement 1 according to the prior art. Reference is made to the explanations regarding the Fig. 1 will be referred.

[0045] Unlike the first embodiment, no shut-off valves 14 are provided, so the piston of the hydraulic cylinder 2 continues to move as the medium is pumped by the pump 4. A simple activation of a start-stop (STO) on the motor 3 only brings the pump 4 to a standstill once the kinetic energy of the motor 3 and the pump 4 has dissipated (provided no external hydraulic forces act on the pump 4). The pump 4 pumps according to its direction of rotation and, if applicable, its swivel angle 11.

[0046] Fig. 3 Figure 1 shows a third embodiment of a hydraulic cylinder arrangement 1 according to the prior art. The explanations regarding the Fig. 2 will be referred.

[0047] This hydraulic cylinder assembly 1 includes a swivel angle control system 5. The hydraulic cylinder assembly 1 comprises a hydraulic cylinder 1 (with piston), a motor 3 for driving an adjustable pump 4, the pump 4, and a swivel angle control system 5 for the pump 4, wherein the swivel angle control system 5 has at least one actuating piston 6 for adjusting the pump 4 and an electrically controlled valve 7 for controlling the actuating piston 6. At least one delivery direction or swivel angle 11 of the pump 4, and thus a movement of the hydraulic cylinder 2 or the piston, can be controlled via the swivel angle control system 5. The pump 4 can be adjusted via the swivel angle control system 5 between -100% (maximum delivery rate of the pump 4 in a first direction), zero% (no delivery of a medium by the pump 4), and +100% (maximum delivery rate of the pump 4 in a second direction).

[0048] If the (swivel angle control) valve 7 is switched to its de-energized basic position analogous to the STO of the motor 3, the swivel angle 11 that is set at the pump 4, and thus whether and in which direction the pump 4 delivers, depends on the valve basic position, the valve pressure supply and the presence of springs in the swivel cradle.

[0049] In a so-called A4 HS5 pump with connected control pressure (pressure port 12) and a de-energized proportional valve or HS5 control valve (as valve 7, i.e., a 4 / 4-way valve), the minimum displacement of the pump 4 is the basic position, which is shown here. In this position, one chamber of the actuating piston 6 is connected to the pressure port 12 and the other chamber of the actuating piston 6 to the return line 13. This basic position is also reached if the HS5 control valve 7 is de-energized due to a fault (e.g., broken cable, etc.). In contrast to an open circuit, where the pump 4 pivots to a minimum end stop (zero percent flow rate), in a closed circuit the pump 4 pivots beyond the zero position to -100 percent flow rate (reversal of direction). In this case, the hydraulic cylinder 2 connected to the pump 4 accelerates maximally in one direction of movement. By implementing a zero-swivel function (see Fig. 4 This behavior can be prevented by ) in the known HS5(E) control system.

[0050] To enable pump 4 to swivel to a swivel angle 11 of zero% when the swivel angle control valve 7 is de-energized, for example, in the case of pump 4 with such an unfavorable basic position of the swivel angle control valve (valve 7), an additional (second) valve 16 and an additional (second) piston 17 or cylinder can be provided (see Fig. 4 ).

[0051] Fig. 4 Figure 1 shows a fourth embodiment of a hydraulic cylinder arrangement 1 according to the prior art. The explanations regarding the Fig. 3 will be referred.

[0052] In contrast to the third version variant, this hydraulic cylinder arrangement 1 provides a second valve 16 and a second piston 17.

[0053] In normal operation of the hydraulic cylinder arrangement 1, the electrically actuated 4 / 4-way valve, acting as the (first) valve 7, regulates the pressure conditions in the actuating piston 6 and thus pivots the pump 4. The first valve 7 is energized and relieves the second piston 17, rendering it ineffective. In the event of a fault in the (first) valve 7, it moves to the illustrated home position, in which one (first) chamber of the actuating piston 6 is connected to the return line 13 and thus relieved of pressure. The other (second) chamber of the actuating piston 6 is connected to the pressure port 12 and thus to the actuating pressure. This causes the actuating piston 6 to move towards the first chamber. To prevent the end position of the actuating piston 6 (in which a maximum delivery rate of the pump 4 is set) from being reached, the second valve 16 is deactivated and connects the second piston 17 or cylinder to the pressure port 12.This causes the second piston 17 to extend to an adjustable end stop (which corresponds to the center position, i.e., the zero percent position of pump 4). The effective area of ​​the second piston 17 is larger than the effective area of ​​the actuating piston 6, thus ensuring that the end position of the second piston 17, or cylinder, is always reached, which again corresponds to the center position, i.e., the zero percent position of pump 4.

[0054] However, the second piston 17 and the second valve 16 are required to implement this hydraulic cylinder arrangement 1.

[0055] Fig. 5 Figure 1 shows a first embodiment of a hydraulic cylinder arrangement. Further details on the... Fig. 1 bis 4 will be referred.

[0056] The hydraulic cylinder assembly 1 comprises a hydraulic cylinder 2, a motor 3 for driving an adjustable pump 4, the pump 4 itself, and a swivel angle control system 5 for the pump 4. The swivel angle control system 5 includes a control piston 6 for adjusting the pump 4 and an electrically controlled valve 7 for controlling the control piston 6. The swivel angle control system 5 allows for the control of at least one delivery direction or swivel angle 11 of the pump 4 (between -100% and +100% of the delivery rate) and thus a movement of the hydraulic cylinder 2. The hydraulic cylinder assembly 1 includes an electrical control unit 8 for operating at least the motor 3 and the valve 7.

[0057] The hydraulic cylinder arrangement 1 also has an uninterruptible power supply 9, so that in the event of a failure of a power supply 10 for the control unit 8, e.g. by actuating the emergency stop switch 15, at least the control unit 8 can be supplied with electrical energy by the uninterruptible power supply 9.

[0058] In the event of a power supply failure 10 for the control unit 8, the valve 7 can be controlled via the energy provided by the uninterruptible power supply 9 so that a swivel angle 11 of the pump 4 can be adjusted to zero % via the actuating piston 6.

[0059] In the event of a power supply failure 10 for the control unit 8, the motor 3 can also be braked to zero rpm via a braking resistor 22 using the energy provided by the uninterruptible power supply 9.

[0060] In particular, the uninterruptible power supply 9 comprises a capacitor 23 or an intermediate circuit connected to the power supply 10, wherein the capacitor 23 or the intermediate circuit provides the energy for the supply of at least the control unit 8 in the event of a failure of the power supply 10.

[0061] The uninterruptible power supply 9 ensures that the hydraulic cylinder 1 comes to a standstill (pump 4 no longer pumps or is in the zero percent position and the motor 3 no longer drives the pump 4).

[0062] The method for operating the hydraulic cylinder arrangement 1 comprises, in the event of a power supply failure 10 according to step a), supplying at least the control unit 8 with electrical energy from the uninterruptible power supply 9. According to step b), the motor 3 is braked to zero rpm by the energy provided by the uninterruptible power supply 9 and the valve 7 is actuated by the energy provided by the uninterruptible power supply, so that a swivel angle 11 of the pump 4 is adjusted to zero % via the actuating piston 6.

[0063] Steps a) and b) are carried out together, meaning that the braking of the motor 3 and the actuation of the valve 7 and thus of the actuating piston 6 are carried out solely by the electrical energy of the uninterruptible power supply 9.

[0064] Without the control of valve 7, valve 7 would otherwise move into the illustrated basic position, in which the actuating piston 6 is moved to one of the end positions, so that the pump 4 would then be adjusted to -100% or +100% swivel angle 11 and the hydraulic cylinder 1 would be moved further.

[0065] In step b), the energy supplied by the uninterruptible power supply 9 is completely consumed. Therefore, after step b), the hydraulic cylinder assembly 1 is de-energized, meaning that no electrical energy remains in the hydraulic cylinder assembly 1 (i.e., in the control unit 8, the uninterruptible power supply 9, or other components).

[0066] Fig. 6 A second embodiment of a hydraulic cylinder arrangement 1 is shown. The descriptions regarding Fig. 5 will be referred.

[0067] In contrast to the first version according to Fig. 5 shows Fig. 6 A hydraulic cylinder arrangement 1 with a differently configured uninterruptible power supply 9. The uninterruptible power supply 9 is designed as an additional 24V power supply 19, which is supplied from the DC link 18. Both power supplies 19 (power supply 19 and power supply of the DC link 18) lead to an additional redundancy module 20. As long as the DC link 18 is still charged, 24V is also available.

[0068] Furthermore, in Fig. 6 A PLC 21 is still supplied with power via the uninterruptible power supply 9. The control of the (rotating angle control) valve 7 is housed in an external electronics unit 24, which is also supplied with power via the uninterruptible power supply 9.

Claims

1. Hydraulic cylinder arrangement (1), comprising at least a hydraulic cylinder (2), a motor (3) for driving an adjustable pump (4), the pump (4) and a swivel angle control system (5) for the pump (4), wherein the swivel angle control system (5) has at least one actuating piston (6) for adjusting the pump (4) and an electrically controlled valve (7) for controlling the actuating piston (6); wherein at least one delivery direction of the pump (4) and thus a movement of the hydraulic cylinder (2) can be controlled via the swivel angle control system (5); wherein the hydraulic cylinder arrangement (1) has an electrical control unit (8) for operating at least the motor (3) and the valve (7); characterized by the fact thatthe hydraulic cylinder arrangement (1) has an uninterruptible power supply (9) so that in the event of a failure of a power supply (10) for the control unit (8) at least the control unit (8) can be supplied with electrical energy by the uninterruptible power supply (9).

2. Hydraulic cylinder arrangement (1) according to claim 1, wherein in the event of a failure of the power supply (10) for the control unit (8) at least the valve (7) can be controlled via the energy provided by the uninterruptible power supply (9) in such a way that a pivot angle (11) of the pump (4) can be adjusted to zero % via the actuating piston (6).

3. Hydraulic cylinder arrangement (1) according to one of the preceding claims, wherein in the event of a failure of the power supply (10) for the control unit (8) at least the motor (3) can be slowed down to zero rpm via the energy provided by the uninterruptible power supply (9).

4. Hydraulic cylinder arrangement (1) according to one of the preceding claims, wherein the uninterruptible power supply (9) comprises a capacitor or an intermediate circuit connected to the power supply (10), wherein the capacitor or intermediate circuit provides energy for the supply of at least the control unit (8) in the event of a failure of the power supply (10).

5. Method for operating a hydraulic cylinder arrangement (1), wherein the hydraulic cylinder arrangement (1) comprises at least one hydraulic cylinder (2), a motor (3) for driving an adjustable pump (4), the pump (4), and a swivel angle control system (5) for the pump (4), wherein the swivel angle control system (5) comprises at least one actuating piston (6) for adjusting the pump (4) and an electrically controlled valve (7) for controlling the actuating piston (6); wherein at least one delivery direction of the pump (4) and thus a movement of the hydraulic cylinder (2) can be controlled via the swivel angle control system (5); wherein the hydraulic cylinder arrangement (1) comprises an electrical control unit (8) for operating at least the motor (3) and the valve (7) and an uninterruptible power supply (9);wherein the procedure in the event of a power supply failure (10) comprises at least the following steps: a) supplying at least the control unit (8) with electrical energy from an uninterruptible power supply (9); and at least b) braking the motor (3) to zero rpm by means of the energy supplied by the uninterruptible power supply (9) or actuating the valve (7) by means of the energy supplied by the uninterruptible power supply (9) so that a pivot angle (11) of the pump (4) is adjusted to zero % via the actuating piston (6).

6. Method according to claim 5, wherein step b) completely consumes the energy provided by the uninterruptible power supply (9).

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