Actuator with position recognition

Abstract

The invention relates to an actuator (5) comprising a drive device (15) which is adapted to move a spindle (20) in a first and a second rotational direction (200), wherein the spindle (20) is connected to a nut (25) such that when the spindle (20) is rotated, the nut (25) is displaced in a third or a fourth translational direction (210), wherein the movement of the nut (25) acts on a deformable portion (30) such that the displacement of the nut (25) is reflected in a deformation of the deformable portion (30). The deformable portion (30) is deformed into a hollow (35) formed between the drive device (15) and the deformable portion (30) and the spindle (20) passes through the deformable portion (30) and the hollow (35).

Description

Technical Field

[0001] This invention relates to actuators, such as actuators for regulating valves. The actuator according to the invention is capable of identifying the position of the actuator. Background Technology

[0002] Actuators used for regulating valves come in a variety of shapes and forms, and include actuators powered by drive mechanisms operated by, for example, gas pressure, hydraulic pressure, or electricity. This allows the actuator, and thus the valve, to be remotely adjusted.

[0003] For some purposes, it is advantageous if the actuator can be compact, thus occupying little space in the valve, for example, little space in the length direction.

[0004] It's also advantageous if the actuator is multifunctional, thus adaptable to different valves. It can also be cheaper to produce if only one or a few versions are needed, and these versions can be adapted to different types of valves, etc. Summary of the Invention

[0005] The purpose of embodiments of the present invention is to provide an actuator capable of accurately identifying at least the end position of the actuator.

[0006] The present invention provides an actuator comprising a drive device adapted to move a spindle along a first rotational direction and a second rotational direction, wherein the spindle is connected to a nut such that when the spindle rotates along the first or second rotational direction, the nut is displaced along a third or fourth translational direction, wherein the displacement of the nut causes the nut to act on a deformable portion such that the displacement of the nut is reflected in the deformation of the deformable portion.

[0007] The deformable portion deforms into a hollow portion formed between the drive device and the deformable portion, and the mandrel passes through the deformable portion and the hollow portion.

[0008] The actuator of the present invention can be, for example, an actuator for a regulating valve. For example, the actuator can be used to drive the movement of a valve element relative to a valve seat, thereby regulating the degree of valve opening.

[0009] The actuator includes a drive mechanism adapted to move the spindle along a first rotational direction and a second rotational direction, i.e., the drive mechanism is adapted to rotate the spindle.

[0010] The spindle is connected to the nut such that when the spindle rotates in a first or second rotational direction, this causes the nut to shift, i.e., the nut performs a translational movement in a third or fourth translational direction. The third and fourth translational directions can advantageously be opposite to each other.

[0011] The displacement of the nut described above causes it to act on the deformable portion, thereby deforming the deformable portion. Therefore, the displacement of the nut is reflected in the deformation of the deformable portion. Thus, the position of the nut along the third or fourth translational direction can be derived from the deformation of the deformable portion. Specifically, based on whether deformation of the deformable portion is detected, it can be deduced whether the actuator is in an end position that causes the nut to act on the deformable portion.

[0012] When the nut, as described above, acts on the deformable portion, the deformable portion deforms into the hollow portion, which is formed or defined between the drive device and the deformable portion. Therefore, as a result of the deformation of the deformable portion caused by the movement of the nut, a portion of the deformable portion moves into or is accommodated in the hollow portion.

[0013] The mandrel passes through the deformable portion and the hollow portion. This can be achieved, for example, by providing an opening in the deformable portion through which the mandrel extends. This ensures that the translational movement of the nut that causes deformation of the deformable portion is precisely defined, and ensures a precisely defined correspondence between the position of the nut and the deformation of the deformable portion. Therefore, the position of the nut can be derived with high precision from the deformation of the deformable portion, and thus the position of the actuator can be derived.

[0014] The first and second rotational directions can be perpendicular to the third and fourth translational directions. According to this embodiment, the rotational movement of the mandrel can occur about a rotation axis arranged parallel to the third and fourth translational directions. The rotation axis can, for example, coincide with the longitudinal direction defined by the mandrel.

[0015] The first rotation direction of the mandrel can be clockwise, and the second rotation direction of the mandrel can be counterclockwise.

[0016] According to this embodiment, the first rotation direction and the second rotation direction represent rotations that are opposite to each other about a suitable axis of rotation (e.g., an axis of rotation that coincides with the longitudinal direction defined by the mandrel).

[0017] The mandrel and the nut may be threaded together, such that clockwise rotation of the mandrel causes the nut to shift along the third direction, and counterclockwise rotation of the mandrel causes the nut to shift along the fourth direction.

[0018] According to this embodiment, the mandrel and nut can be connected to each other by a threaded connection formed by an external thread on the mandrel and an internal thread on the nut. The nut can be locked to prevent rotational movement, but translational movement relative to the mandrel is permitted along a longitudinal direction defined by the mandrel. Thus, when the mandrel rotates, the nut is not allowed to rotate with it, but the threaded connection causes the nut to translate relative to the mandrel. Therefore, the threaded connection ensures that the rotational movement of the mandrel is converted into the translational movement of the nut. More specifically, the threaded connection ensures that rotational movement of the mandrel in a first direction (i.e., clockwise) causes the nut to translate in a third direction, while rotational movement of the mandrel in a second direction (i.e., counterclockwise) causes the nut to translate in the opposite direction (i.e., a fourth direction).

[0019] The deformable portion can extend in a plane parallel to the first and second rotational directions. According to this embodiment, the rotational movement of the mandrel occurs about a rotational axis that extends substantially normally to the plane defined by the surface of the deformable portion. Consequently, the resulting translational movement of the nut will occur along a direction having a component normal to the plane defined by the surface of the deformable portion. Therefore, when the nut moves as described above, it pushes the deformable portion along this normal direction, thereby causing a clearly defined deformation of the deformable portion.

[0020] Multiple deformable protrusions may be distributed within the nut along lines parallel to the third and fourth translational directions, and each deformable protrusion may be adapted to block a portion of the mandrel when it passes a protrusion during the displacement of the nut, thereby increasing the power required by the drive device to induce rotational motion of the mandrel.

[0021] According to this embodiment, the nut has a plurality of deformable protrusions distributed along the direction in which the nut is displaced (i.e., along the third and fourth translational directions). Furthermore, the spindle has portions that can be blocked by the protrusions of the nut, for example, in the form of a widened portion of the spindle. When the nut is displaced relative to the spindle, this results in relative movement between the protrusions of the nut and the widened portion of the spindle. When the protrusions and the widened portion of the spindle are arranged in an overlapping position, the engagement between the protrusions and the widened portion will prevent further relative movement between the nut and the spindle. This means that the drive device needs to overcome an additional force to rotate the spindle and thereby cause further displacement of the nut. Overcoming this additional force requires additional power from the drive device. When this additional power requirement from the drive device is detected, it can be determined that the position of the nut corresponds to the position that causes the positions of the protrusions and the widened portion to coincide. Therefore, such information can be used to determine the position of the nut, and thereby determine the position of the actuator.

[0022] Therefore, the protrusion can be used to estimate the position of the nut.

[0023] The actuator can communicate with the controller for data exchange, and the deformation characteristics of the deformable part can be stored in the controller. The controller is adapted to detect the operating parameters of the drive device and to estimate the position of the nut based on the detected operating parameters and the stored deformation characteristics.

[0024] According to this embodiment, based on the known deformation characteristics of the deformable part and the relevant operating parameters of the drive device related to the deformation characteristics, the position of the nut can be derived from the deformation of the deformable part, and thus the position of the actuator can be derived.

[0025] The operating parameters can be the driving voltage or driving current of the driving device.

[0026] When the translational movement of the nut causes deformation of the deformable portion, this indicates a force acting in the opposite direction to the translational movement of the nut. Therefore, to move the nut, the actuator requires more power. This will result in a higher drive voltage and / or a higher drive current. Thus, the drive voltage or drive current provides information about whether the nut is in an end position, where the movement of the nut causes deformation of the deformable portion. For example, if the drive voltage or drive current of the actuator exceeds a certain threshold, this can indicate that the actuator has reached the end position and therefore should not move further.

[0027] The driving device can be a motor, such as an electric motor. Attached Figure Description

[0028] The invention will now be described in further detail with reference to the accompanying drawings, in which,

[0029] Figure 1 and Figure 2 This is a cross-sectional view of an actuator according to an embodiment of the present invention;

[0030] Figure 3 The illustration shows the drive power of the actuator drive device as a function of the actuator position according to an embodiment of the present invention;

[0031] Figure 4 The illustration shows the drive current of the actuator drive device as a function of the actuator position according to an embodiment of the present invention;

[0032] Figure 5 The illustration shows a portion of the nut and spindle of an actuator according to an alternative embodiment of the invention; and

[0033] Figure 6 The diagram illustrates the following: Figure 5 The driving power of the actuator driving device in the embodiment is a function of the position of the actuator. Detailed Implementation

[0034] It should be understood that since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from the detailed description, the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only.

[0035] Figure 1 The illustration shows an actuator 5 including a drive unit 15 adapted to move a spindle 20 along a first direction and a second direction 200. The drive unit 15 may be an electric motor, an air motor, a pneumatic actuator, an electroactive actuator, or any other suitable device 15 adapted to move the spindle 20.

[0036] In the illustration, a spindle 20 is connected to a nut 25 such that movement of the spindle 20 along a corresponding first or second direction 200 causes the nut 25 to shift along a third or fourth direction 210. In one embodiment, the spindle 20 and the nut 25 are threadedly connected, and the first and second directions 200 are rotations about a longitudinal axis relative to the spindle 20, for example, clockwise and counterclockwise, respectively. In this embodiment, as the spindle 20 rotates, the threaded connection causes the nut 25 to shift along the spindle 20 in the length direction, for example, upward and downward, depending on the direction of rotation of the spindle 20. This shift along the spindle 20 is respectively the third and fourth directions 210.

[0037] For example, a clockwise rotation of the spindle 20 can cause the nut 25 to shift in a third direction, while a counterclockwise rotation of the spindle 20 can cause the nut 25 to shift in a fourth direction, or vice versa.

[0038] In one embodiment, the first and second directions of motion 200 are perpendicular to the third and fourth directions 210. For example, this is when the first and second directions 200 are rotating about the longitudinal axis relative to the mandrel 20, and the third and fourth directions 210 are along the longitudinal direction of the mandrel 20.

[0039] The deformable portion 30 is positioned such that it can be reshaped or deformed by the movement of the mandrel 20 and the nut 25. The illustrated embodiment shows the deformable portion 30 positioned in contact with the nut 25 such that the position of the nut 25 defines the shape or deformation of the deformable portion 30.

[0040] The deformable portion 30 can be formed of a bendable element, a spring element, or any material or shape having a basic shape but adapted to deform or change shape when subjected to force. In this context, deformation can be bending when pushed, compression (e.g., compression of a spring), or, for example, when squeezed between two parts. In the example below, the deformation is bending, but this can be replaced by, for example, a compressed spring.

[0041] The deformable portion 30 can then be positioned such that it has a basic shape at the end positions of the spindle 20 and / or the nut 25, for example, the end positions of the spindle 20 and / or the nut 25 corresponding to the fully open or closed position of the valve connected to the actuator 5.

[0042] This embodiment illustrates a segment of the spindle 20 positioned within a nut 25 and an end portion 20a. The interior of the nut 25 defines an end point 45 for one end portion 20a of the spindle 20, which is closed, for example, by the nut 25. As the spindle 20 moves along a first or second direction 200, for example by rotation, its position within the nut 25 will change by displacement along a third and fourth direction 210. When the end portion 20a reaches the end point 45, it cannot be displaced any further without the risk of damaging the nut 25. It is possible that the drive mechanism 15 could also be damaged due to high resistance encountered.

[0043] The nut 25 has a threaded opening at one end, which is adapted to allow the spindle 20 to contact and reach the interior of the nut 25. The interior of the nut 25 has a hollow portion, which may also be threaded and in contact with the spindle 20, or, as shown, the hollow portion is formed such that there is no contact between the spindle 20 and the inside of the hollow portion. The threaded opening may be located at the opposite end of the nut 25 to end point 45.

[0044] The deformable portion 30 can be positioned to contact one of the outer end surfaces of the nut 25, for example, at the end with a threaded opening. Alternatively, the deformable portion 30 can be positioned to contact an end point 45 of the nut 25, which may also contact a valve or a portion thereof, such as a movable valve stem. Alternatively or additionally, the nut 25 may have a protrusion somewhere along the outer side of the nut 25 that can contact the deformable portion 30.

[0045] As illustrated, the deformable portion 30 is positioned between the nut 25 and the drive unit 15. When between the surfaces of other portions, such as between the surfaces of the nut 25 and the drive unit 15, the deformable portion 30 may require space for deformation or reshaping. For this purpose, a hollow portion 35 is formed between the deformable portion 30 and one of these surfaces, for example, in the illustrated embodiment, a hollow portion 35 is formed between the drive unit 15 and the deformable portion 30.

[0046] The hollow portion 35 can be formed by inserting at least one separating element 40, which is sandwiched between two stationary elements of the actuator 5, such as the drive unit 15 and the actuator housing 10, or some other inserted stationary feature within the housing 10. One or more separating elements 40 can be arranged circumferentially relative to a deformable region 30a of the deformable portion 30, which is the portion of the deformable portion 30 that contacts, for example, the nut 25. One or more separating elements 40 can have a wider width than the deformable region 30a and are positioned such that when the deformable portion 30 is in its base shape, it maintains a distance from, for example, the drive unit 15, which forms the hollow portion 35.

[0047] In the illustrated embodiment, the separating element 40 is an integral protrusion 40 of the deformable portion 30, for example, located at the periphery of the deformable portion 30. In an alternative embodiment, the edge of the deformable element 30 may be clamped, for example, between the housing 10 and the separating element 40.

[0048] The deformable portion 30 may be, for example, disc-shaped and positioned in the actuator 5 to extend in a plane parallel to the first and second directions 200.

[0049] The mandrel 20 can pass through the deformable portion 30 and the hollow portion 35, and thus the deformable region 30a can be formed with an opening for the mandrel 20. The size of this opening is such that the inner periphery of the opening does not contact the mandrel 20. In an alternative embodiment, the opening can be threaded onto the mandrel 20 such that movement of the mandrel 20 along the first and second directions 200 causes deformation of the deformable region 30a of the deformable portion 30, rather than deformation of the nut 25.

[0050] Figure 1 The nut 25 is shown to contact an inner section of the deformable region 30a, for example, the inner edge periphery of the opening for the spindle 20, but no deformation force is acting on the deformable portion 30, so that the deformable portion 30 is in its basic form.

[0051] Figure 1The diagram shows that the nut 25 contacts the valve stem 100 of the valve, such that displacement of the nut 25 in a third or fourth direction 210 correspondingly displaces the valve stem 100 to change the position of the valve element and thereby change the valve opening.

[0052] Figure 2 Is with Figure 1 The same actuator 5 is illustrated, but the nut 25 is further displaced toward the deformable portion 30, thereby deforming the deformable region 30a of the deformable portion 30 into the hollow portion 35.

[0053] When the deformable region 30a is pushed by the nut 25, the deformation or reshaping of the deformable region 30a is considered as bending.

[0054] The purpose of the deformable portion 30 includes at least identifying when the mandrel 20 is in an end position, such as when an end portion 20a contacts or is close to the end point 45, as illustrated.

[0055] Since additional power from the drive unit 15 is required to deform the deformable portion 30 compared to the case where such a deformable portion 30 does not exist, this deformation can be estimated. This is because the power will increase as a function of the deformation (e.g., bending), and the relationship is not linear. This is in Figure 3 The diagram illustrates the power P required to move the nut 25 a distance D due to the increased deformation / bending of the deformable portion 30. Such a relationship as this deformation characteristic can be stored, for example, in a data storage device such as a processor in the controller of the actuator 5, or in the actuator 5 itself. When a given power consumption P is measured, and once a given threshold power consumption is reached, the system recognizes this as the spindle 20 having reached or approached end point 45, and stops any further movement in that direction.

[0056] Figure 4 An alternative is shown in which the current I associated with the travel distance D is stored in the processor's data storage device, and in which the current I induced by the drive device 15 is measured, and when a given threshold current is reached, the system recognizes this as the spindle 20 having reached or approached the endpoint 45, and stops any further movement in that direction.

[0057] Figure 5 An embodiment that can be used to improve the position recognition of nut 25 is shown. The basic idea is to include multiple blocking portions along the path of nut 25. The illustrated embodiment introduces a protrusion 50 formed in the inner wall of the hollow nut 25.

[0058] The spindle 20 may be formed with a widened portion 55, which is adapted to engage with the respective protrusions 50 as they pass each other.

[0059] The protrusion 50 and / or possible widening portion 55 may be elastic enough to allow them to be slightly compressed, for example. For instance, if the protrusion 50 is elastic, the widening portion 55 may come into contact with it as the protrusion 50 and spindle 20 pass each other, with the elastic portion providing additional resistance. Due to its elasticity, the elastic portion is slightly compressed, thus allowing passage. Therefore, the drive unit 15 needs to use some additional power to force the protrusion 50 past the spindle 20, or vice versa, depending on whether the observation point is from the spindle 20 or from the nut 25.

[0060] Figure 6 The diagram illustrates how this additional obstruction causes a slight increase or protrusion in the curve relating power consumption P to travel distance D. The system (e.g., a processor) can then be adapted to "count" the number of protrusions 50 crossed by the spindle 20, and this number can then be used to "calibrate" the positional identification of the nut 25 relative to the spindle 20, corresponding to the travel distance D.

[0061] The present invention relates to the function of the deformable portion 30 for estimating, for example, the position of an end point, such as the end point 45 within the nut 25, and / or generally for estimating position. The nut 25 and its engagement with the mandrel 20 can be operated differently, for example, the mandrel 20 can be moved along a first displacement direction and a second displacement direction 200 that may be parallel to a third direction and a fourth direction 210.

[0062] In one embodiment, the mandrel 20 directly actuates, for example, the valve stem 100, and therefore does not include the nut 25. Also in this embodiment, the concept of a deformable portion 30 can be used to identify the location of the mandrel 20 and possible end positions. The deformable portion 30 can then be connected to or contact the mandrel 20 to bend, compress, or reform.

Claims

1. An actuator (5) comprising a drive (15) adapted to move a spindle (20) along a first rotational direction and a second rotational direction, wherein the spindle (20) is connected to a nut (25) such that when the spindle (20) rotates along the first rotational direction or the second rotational direction, the nut (25) is displaced along a third translational direction or a fourth translational direction, wherein the displacement of the nut (25) causes the nut (25) to act on a deformable portion (30) such that the displacement of the nut (25) is reflected in the deformation of the deformable portion (30). Its features are, The deformable portion (30) deforms into a hollow portion (35) formed between the drive device (15) and the deformable portion (30), and the spindle (20) passes through the deformable portion (30) and the hollow portion (35), wherein a plurality of deformable protrusions (50) are distributed within the nut (25) along lines parallel to the third translation direction and the fourth translation direction, each deformable protrusion (50) being adapted to block the portion (55) of the spindle (20) when a portion (55) of the spindle (20) passes through the protrusion (50) during the displacement of the nut (25), thereby increasing the power required by the drive device (15) to cause the rotational motion of the spindle (20).

2. The actuator (5) according to claim 1, wherein, The first rotation direction and the second rotation direction are perpendicular to the third translation direction and the fourth translation direction.

3. The actuator (5) according to claim 1, wherein, The first rotation direction of the spindle (20) is clockwise, and the second rotation direction of the spindle (20) is counterclockwise.

4. The actuator (5) according to claim 3, wherein, The mandrel (20) and the nut (25) are threaded together such that clockwise rotation of the mandrel (20) causes the nut (25) to shift along the third translational direction, and counterclockwise rotation of the mandrel (20) causes the nut (25) to shift along the fourth translational direction.

5. The actuator (5) according to any one of claims 1 to 4, wherein, The deformable portion (30) extends in a plane parallel to the first rotation direction and the second rotation direction.

6. The actuator (5) according to claim 1, wherein, The protrusion (50) is used to estimate the position of the nut (25).

7. The actuator (5) according to any one of claims 1 to 4, wherein, The actuator (5) communicates with the controller for data exchange, and the deformation characteristics of the deformable part (30) are stored in the controller. The controller is adapted to detect the operating parameters of the drive device (15) and to estimate the position of the nut (25) based on the detected operating parameters and the stored deformation characteristics.

8. The actuator according to claim 7, wherein, The operating parameters are the driving voltage or driving current of the driving device (15).

9. The actuator according to any one of claims 1 to 4, wherein, The drive device (15) is a motor.

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