WO2020224751A1

WO2020224751A1 - Method for monitoring the function of a spring assembly of an actuator, and actuator

Info

Publication number: WO2020224751A1
Application number: PCT/EP2019/061450
Authority: WO
Inventors: Michael Noll
Original assignee: Auma Riester Gmbh & Co. Kg
Priority date: 2019-05-03
Filing date: 2019-05-03
Publication date: 2020-11-12
Also published as: EP3963239A1

Abstract

The invention relates to a method for monitoring the function of a spring assembly, in particular a spring nest (18), of an actuator (1), wherein, in the tensioned state of the spring assembly (18), a measured value of a measurand correlating with the spring force of the spring assembly (18) is detected (20), and the detected measured value of the measurand is compared with a reference value (21).

Description

Method for monitoring the function of a spring arrangement of a

Actuator and actuator

The invention relates to a method for monitoring the function of a spring arrangement, in particular a spring nest, of an actuator. Such actuators are known and are used in industrial systems, for example to operate fittings. It has become customary to use a spring or a spring arrangement in order to enable reliable actuation of the valve in a desired direction even if, for example, the power supply to the actuator fails.

For this purpose, the spring arrangement serves as an energy store and is usually also used to enable actuation in one desired direction during normal operation, while the preferably electromagnetic actuator is used to tension the spring arrangement in the other actuation direction. In order to monitor the functioning of the spring arrangement, it has become common practice to carry out so-called diagnostic drives with which the spring arrangement is relaxed in order, for example, to detect spring breakages or bearing damage or other occurrences which impede its function. However, this has the disadvantage that normal operation is disturbed because at the time of

Diagnostic drive, for example, no actuation of the valve was required. In particular, this causes the valve to be closed or opened unnecessarily, both of which have undesired consequences may have.

In particular in the field of raw material extraction, for example, it is very unfavorable if a continuous process is disrupted.

In the prior art it is therefore also known to carry out the diagnostic travel only halfway through the travel range, so that the valve is at least semi-permeable.

The object of the invention is therefore to create an alternative diagnostic method.

This object is achieved by a method with the features of claim 1 and by an actuator according to claim 6.

The method is particularly characterized in that when the spring arrangement is in the tensioned state, a measured value of a measured variable correlating with a spring force of the spring arrangement is recorded and that the recorded measured value of the measured variable is compared with a reference value.

In this way, information can be provided that the springs are ready for operation. Contrary to the state of the art, no diagnostic drive is necessary for this. Rather, such a measurement can be carried out periodically, regularly or continuously, for example, in order to detect damage during operation.

The reference value can be a fixed, predetermined value or an earlier measured value, or it can be determined by a one-time diagnosis or initialization run. A spring arrangement has at least one spring, the measured variable correlating with the spring force of the at least one spring.

It is particularly advantageous if the spring arrangement has at least two, but preferably several springs. It can be particularly expedient if the spring arrangement is a spring nest, which can be characterized, for example, by the fact that several or many springs act in parallel or in series with one another. It can therefore store a lot of energy in a small space and is therefore also suitable for operating large fittings.

In one embodiment of the invention it can be expedient if the measured variable is also monitored in the relaxed state and / or during operation and / or continuously and the measured values are each compared with previous measured values and / or reference values. In this way, it is possible, for example, to detect the existence of bearing damage which, even if the spring arrangement was functional, would prevent actuation or travel in an emergency because the spring force is then no longer sufficient.

It is also possible to save several earlier measured values in order to obtain a chronological sequence. In this way, for example, a gradual deterioration of the springs, bearings or transmission components can be detected at an early stage.

In an advantageous embodiment of the invention, the measured variable is a torque on the drive shaft for tensioning the spring arrangement or a torque that correlates with the torque Measured variable recorded. In this way, for example, already existing electronics can also be used to evaluate a torque load on the drive shaft, which is intended to protect a valve from overload, for example.

It can be particularly useful if the torque is detected in a gear of the actuator. For this purpose, an axial deflection of a worm can be measured in a worm gear, for example. However, other types of torque measurement are also known, for example via strain gauges or via corresponding loading and rotation of moving parts, for example of a superposition gear.

In an expedient embodiment of the invention, if the measured value deviates from a reference value, an error state is signaled and / or an emergency position of the actuator is approached.

The invention further comprises an actuator with a drive motor and with a spring arrangement, in particular a spring nest, which can be tensioned by the drive motor. The actuator according to the invention is particularly characterized in that it has a measuring means for detecting a measured variable that correlates with the spring force of the spring arrangement and that, when the spring arrangement is in the tensioned state, a measured value of the measured variable can be recorded and the measured value is comparable to a reference value.

The valve and / or the actuator can perform a linear movement, a rotary movement or a pivoting movement. In this way, it is easy to determine whether the spring or springs of the spring arrangement still have sufficient force or whether there is a malfunction.

The reference value can be a specified reference value or a previous measured value. A hysteresis or a tolerance, for example, can also be used to compare the measured value with the reference value.

In an expedient embodiment of the invention, the measured variable can also be recorded in the relaxed state and / or during operation and / or continuously. As a result, not only errors or damage to the springs can be detected, but also bearing damage or other problems can be identified, which would prevent the actuator from operating properly.

It can be particularly advantageous if the actuator has a worm gear and the torque is recorded by measuring an axial deflection of a worm of the worm gear.

So that a valve or the actuator can be moved into a rest position by the spring arrangement, it is useful if the actuator has a non-self-locking gear, in particular worm gear.

In order to prevent undesired movement in the non-self-locking gear, in particular worm gear, it is useful if a brake unit is coupled to the drive shaft and the measuring means is arranged between this brake and the spring arrangement. The brake unit preferably has an electric brake, which by a Motor or control electronics is activated.

In an alternative embodiment of the invention, the actuator has a superposition gear, with a locking mechanism being present which prevents the springs of the spring arrangement from relaxing undesirably. In this embodiment, the spring arrangement is connected to the superposition gear in such a way that it superimposes the movement of the drive shaft.

In one embodiment of the invention, it can be useful if the actuator has a spindle nut coupled to the drive shaft, which moves a pressure plate linearly, one end of the springs of the spring arrangement being attached to the pressure plate so that the springs move in a linear fashion let the pressure plate tension.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying drawings.

It shows:

1: a functional block diagram of an actuator according to the invention,

Fig. 2: a block diagram of an inventive

Actuator,

3: a block diagram of an inventive

Actuator,

Fig. 4: a flow chart of a method according to the invention and 5: a status diagram of an actuator according to the invention.

1 shows a schematic functional block diagram of an actuator 1 according to the invention. The actuator 1 has an electric drive motor 2 as an electric opening and spring tensioning unit, a control and monitoring unit 3, a holding and braking unit 4 and a spring-mechanical closing unit 5. The actuator 1 serves for example to drive a gate valve 6 or another valve.

FIG. 2 shows a block diagram of an actuator 1 according to the invention. The actuator 1 has a drive motor 2 which is connected to a gear 7, a brake unit 4 being arranged between the drive motor 2 and the gear 7. The brake unit 4 has an electric brake, for example, so that the braking effect can be controlled continuously and in a targeted manner. The drive motor 2 and the brake unit 4 are connected to a control and monitoring unit 3 and can be controlled.

The gear 7 can for example be a worm gear, in particular a non-self-retaining worm gear. Means for detecting the torque on the drive shaft and the position are arranged on the transmission 7.

The torque can be determined, for example, using a strain gauge or by determining an axial deflection of a worm in the worm gear.

At the output of the transmission 7 there is a spring arrangement in the form a spring nest 5 which can be tensioned by the drive motor 2 and which acts on a fitting 6.

In the example, the actuator 1 is used to drive a valve 6. The example also shows a switch box 19 which is used to supply the actuator 1 with electrical power.

FIG. 3 shows a further block diagram of an actuator 1 according to the invention. As in FIG. 2, the drive motor 2 is connected to a brake unit 4. The transmission 7 has a drive shaft 8 with a worm. A means for detecting the torque 9 is arranged on this drive shaft 8.

The transmission 7 also has a hollow shaft 10 with a worm wheel. A means for detecting the position or a distance 11 is arranged on this hollow shaft 10.

The means for detecting the torque 9 and the distance 11 are connected to the control and monitoring unit 3 via a changeover switch 12.

Finally, the transmission 7 has an output sleeve 14 which is connected to the spring-mechanical locking unit 5. In the example, the closing unit 5 serves to convert the rotary movement of the gear output 14 into a linear movement for actuating the valve 6. It is also used to move a valve 6 into a defined position in the event of a power failure or a defective drive motor 2 by spring force.

The closing unit 5 has a spindle nut 15 and a spindle 16. The spindle nut 15 transmits the rotary movement the output sleeve 14 in a linear movement of the spindle 16. The spindle 16 serves as an actuating element for a valve 6.

The spindle 16 is also rigidly connected to a pressure plate 17 so that the pressure plate 17 is also moved linearly. The pressure plate 17 is connected on one side to the ends of the springs of a spring nest 18 as a spring arrangement, the springs being arranged around the spindle 16 in the axial direction. The springs are tensioned by the linear movement of the spindle 16. Conversely, the springs of the spring nest 18 act directly on the spindle 16 if the drive motor 2 fails.

According to the invention, the diagnosis of the spring nest according to FIG. 4 now takes place in that the torque on the drive shaft 8 is measured or detected at least when the springs are in the tensioned state 20. The advantage now is that an actuator 1 usually already has a means for detecting the torque a drive shaft, for example to prevent damage to a valve due to overload. No further sensors or additional components are therefore necessary for the method according to the invention. In particular, a complex construction, for example to ensure explosion protection, can be dispensed with.

The detected torque is now compared with a reference value 21. This reference value can be a predetermined value which was calculated, for example, from the spring constants of the springs used in the spring nest. However, an earlier measured value, for example a first initialization run, can also be used as a reference value. However, several earlier measured values can also be saved over time. A reference value can for example, can also be calculated as the mean value of several previous measured values. Alternatively, it is also possible to continuously record the measured values in order to also detect other defects, for example bearing or gear damage.

As long as the springs exert a constant spring force, the torque required for tensioning on the drive shaft 8 is also the same. Deviations in the torque therefore reliably signal when there is an error.

If the measured value corresponds to the reference value, operation 22 of the actuator is continued or started. The detection 20 of the torque then takes place again, for example, after a defined time interval or when the actuator has made a journey.

When comparing 21 the measured value with the reference value, a tolerance threshold or a hysteresis can also be used. In this way, slight irregularities in the measuring process or the measuring accuracy can be ignored.

However, if the measured value does not correspond to the reference value, an error is detected 23. In the example, the actuator then moves 24 to an emergency position and stops operation 25.

Alternatively or additionally, an alarm signal and / or error signal can be generated. It can also be advantageous if the error signal is transmitted to a receiver.

5 shows a status diagram of an actuator according to the invention.

/ List of reference symbols List of reference symbols

1 actuator

2 drive motor

3 control and monitoring unit

4 braking unit

5 clamping unit

6 fitting

7 gears

8 drive shaft

9 means for detecting a torque

10 hollow shaft

11 means for recording a distance

12 changeover switches

14 output sleeve

15 spindle nut

16 spindle

17 pressure plate

18 spring arrangement, especially spring nest

20 Record torque

21 Compare torque with reference value

22 Operation

23 Identifying errors

24 Approach emergency position

25 Stopping operation

/Expectations

Claims

Expectations

1. A method for monitoring the function of a spring arrangement, in particular a spring nest (18), an actuator (1), characterized in that in the tensioned state of the spring arrangement (18) a measured value of a measured variable correlating with a spring force of the springs is recorded (20) and that the recorded measured value of the measured variable is compared with a reference value (21).

2. The method according to claim 1, characterized in that the measured variable is also monitored in the relaxed state and / or during operation and / or continuously and the measured values are compared with previous measured values and / or reference values.

3. The method according to claim 1 or 2, characterized in that a torque on the drive shaft (8) for tensioning the spring arrangement (18) or a measured variable correlating with the torque is recorded as the measured variable.

4. The method according to claim 3, characterized in that the torque is detected in a gear (7) of the actuator (1).

5. The method according to any one of claims 1 to 4, characterized in that if the measured value deviates from a reference value, an error state is signaled (23) and / or that an emergency position of the actuator is approached (24).

6. actuator (1), with a drive motor (2) and with a spring arrangement, in particular a spring nest (18), which can be tensioned by the drive motor (2), characterized in that the actuator (1) has a measuring means for detecting a measured variable correlating with a spring force of the spring arrangement (18) and that in a tensioned State a measured value of the measured variable can be recorded and the measured value is comparable with a reference value.

7. Actuator (1) according to claim 6, characterized in that the measured variable can also be recorded in the relaxed state and / or in operation and / or continuously.

8. Actuator (1) according to claim 6 or 7, characterized in that a torque on a drive shaft (8), with which the springs can be tensioned, or a measured variable correlating with the torque can be detected as the measured variable.

9. Actuator (1) according to one of claims 6 to 8, characterized in that the actuator (1) has a worm gear (7) and the torque is detected by measuring an axial deflection of a worm of the worm gear (7).

10. Actuator (1) according to one of claims 6 to 9, characterized in that the actuator (1) has a non-self-locking worm gear.

11. Actuator (1) according to one of claims 6 to 10, characterized in that a brake unit (4) is coupled to the drive motor (2) and that the measuring means are arranged between the brake unit and the spring arrangement and / or that the measuring means (9, 11) are arranged in a transmission (7).

12. Actuator (1) according to one of claims 6 to 11, characterized in that the actuator (1) has a spindle nut (15) which is coupled to the drive shaft (8) and which moves a pressure plate (17) linearly, wherein on the pressure plate (17) each one end of the springs of the spring arrangement (18) are attached so that the springs can be tensioned by a linear movement of the pressure plate (17).

13. actuator (1) according to any one of claims 6 to 12, characterized in that the actuator (1) has a superposition gear, wherein a

There is a locking mechanism which prevents the springs of the spring arrangement (18) from relaxing undesirably.

/Summary