Rotary drive having a position detection device and calibration method

Abstract

A rotary drive for actuating a valve element of a valve fitting, having a housing, which has a drive device and a pivot-mounted driven shaft which can be driven by the drive device and which can be coupled to the valve element, and a position detection device for detecting a position of the driven shaft, wherein the position detection device has a magnet module attached to the driven shaft in a torque-proof manner and a sensor module which is fitted onto or into the housing and is designed to detect a magnetic field measurement value according to the magnetic field generated by the magnet module. The the magnet module and/or the sensor module is attached such that it can be removed from the rotary drive, and the rotary drive includes a control device, which is adapted to determine if the magnet module or the sensor module is removed from the rotary drive.

Claims

1. A calibration method for a rotary drive for actuating a valve element of a valve fitting, the rotary drive having a housing, which has a drive device and a pivot-mounted driven shaft which can be driven by the drive device, and which can be coupled to the valve element, and a position detection device for detecting a position of the driven shaft, wherein the position detection device has a magnet module that can be attached to the driven shaft in a torque-proof manner and a sensor module which is fitted onto or into the housing and which is designed to detect a magnetic field measurement value according to the magnetic field generated by the magnet module, the rotary drive further comprising a control device, the method comprising: attaching the magnet module to the driven shaft; determining with the control unit, according to the magnetic field measurement value, that the magnet module is being attached to the driven shaft; and triggering a calibration process based on the determined attachment of the magnet module, wherein the calibration process comprises moving the driven shaft to a predefined position and the control unit storing a magnetic field measurement value, which is detected by the magnet module, in assignment to the predefined position.

2. The calibration method according to claim 1, wherein the control device stores the detected magnetic field measurement value in assignment to the predefined position of the driven shaft if for a predefined period of time the magnetic field measurement value detected by the sensor module is constant within a predefined tolerance range.

3. The calibration method according to claim 1, wherein the rotary drive is fluid-actuated and the drive device comprises a piston space, a drive piston arrangement, which is arranged in the piston space, is mechanically coupled to the driven shaft and subdivides the piston space into a plurality of chambers, and a control valve arrangement which supplies at least one of the chambers with a pressurised fluid.

4. The calibration method according to claim 1, wherein an axial end of the driven shaft is brought out of a wall section of the housing and, in the step of attaching the magnet module to the driven shaft, the magnet module is attached onto the axial end of the driven shaft.

5. The calibration method according to claim 1, wherein the magnet module is adapted as a position indicator which has an indicating element for visually indicating a position of the driven shaft and a magnet arrangement.

6. The calibration method according to claim 1, wherein the sensor module is arranged in a receiving chamber in a wall section of the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a perspective illustration of a rotary drive according to a first embodiment,

(2) FIG. 2 shows a perspective cross-sectional illustration of the rotary drive according to the first embodiment,

(3) FIG. 3 shows an exploded illustration of the rotary drive according to the first embodiment,

(4) FIG. 4 shows a perspective illustration of the rotary drive according to a second embodiment,

(5) FIG. 5 shows an exploded illustration of a rotary drive according to the second embodiment,

(6) FIG. 6 shows a perspective illustration of a magnet module of a rotary drive according to the first and second embodiments,

(7) FIG. 7 shows a view from below of a magnet module of a rotary drive according to the first and second embodiments and

(8) FIG. 8 shows a perspective illustration of a process valve assembly according to a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) In the description of the figures below, the same names are used for components of the illustrated embodiments which have the same functions, wherein a repeated description of components which have the same functions is omitted.

(10) FIGS. 1 to 3 show perspective illustrations of a rotary drive 40 according to a first embodiment.

(11) The rotary drive 40 of the first embodiment is suitable for attaching to a valve fitting 24, in order to actuate a valve element of the valve fitting 24 and thus manipulate a fluid flow.

(12) As shown in FIGS. 1 to 3, the rotary drive 40 comprises a housing 1 which has a drive device and a pivot-mounted driven shaft 6 which can be driven by the drive device. In the example shown in FIG. 2, the drive device in particular comprises a piston space 11 and a drive piston arrangement 19. The rotary drive 40 is hence fluid-actuated in the example shown. Alternatively, the rotary drive according to the invention can also be designed as an electromagnetic rotary drive.

(13) The rotary drive 40 comprises a position detection device for detecting a position of the driven shaft 6. The position detection device in particular comprises a magnet module 23 which is adapted as a position indicator and is removably attached or fitted onto an axial end of the driven shaft 6 brought out of the housing 1. The magnet module 23 is connected to the driven shaft 6 in a torque-proof manner.

(14) The position detection device also comprises a sensor module 36 which is arranged in a receiving chamber in a wall section 35 of the housing 1. The wall section 35 is the same wall section, out of which the axial end of the driven shaft 6 is brought.

(15) The magnet module 23 comprises a magnet arrangement 34 which generates a magnetic field. The sensor module 36 is adapted to detect a magnetic field measurement value according to the magnetic field generated by the magnet module 23.

(16) The rotary drive 40 further comprises a control device which in the example shown is integrated into the sensor module 36 and forms part of the position detection device. The control device is adapted to determine, according to the magnetic field measurement value detected by the sensor module 36, whether the magnet module 23 has been removed from the rotary drive 40 or the driven shaft 6 and, depending on the determination made, to cause the rotary drive to be put into a predefined operating state.

(17) In the example described here, the control device is adapted to, when it has been determined that the magnet module 23 has been removed, adopt an error state and provide a corresponding error signal which shows that, at the moment, position detection is not possible. Preferably, the control device is also adapted to deleted, in the error state, magnetic field measurement values stored and assigned to the two end positions.

(18) Alternatively or in addition to this, the control device may be adapted to, when it has been detected or determined that the magnet module has been removed, adopt one of the above described operating states, in particular a ventilation state, a maintenance state or an emergency shutdown state.

(19) The control device is further adapted to determine or recognise, according to the magnetic field measurement value detected by the sensor module 36, that the magnet module 23 is being mounted onto the axial end of the driven shaft 6. In this case, the control device adopts a calibration state. In particular, the control device is adapted to store, in the calibration state, a magnetic field measurement value in assignment to an end position of the driven shaft if for a predefined period of time the magnetic field measurement value is constant within a predefined tolerance range.

(20) The end positions of the driven shaft can be mechanically set by the user via the positioning means 33A and 33B. The driven shaft 6 may be moved to the end positions by issuing corresponding control commands to a control valve arrangement assigned to the rotary drive. The control commands may be issued to the control valve arrangement by the control device or by an external control unit.

(21) In the example shown in FIG. 1, the magnet module 23 is designed as a position indicator which comprises an indicating element 39, via which the position of the driven shaft may be visually determined by a user.

(22) FIG. 2 shows a cross-sectional illustration of the rotary drive 40. Here, in particular the drive piston arrangement 19 arranged in a piston space 11 and consisting of two drive pistons can be seen. The two drive pistons comprise respective toothed racks (not shown here) which are aligned in the axial direction and are in intermeshing engagement with a driven pinion gear arranged on the driven shaft 6, in order to convert a linear movement of the drive pistons into a rotational movement of the driven shaft 6. In particular, the toothed racks are arranged on opposite sides of the driven shaft 6, so that opposed linear movements of the drive pistons are converted into respective rotational movements of the driven shaft 6. In this way, the driven shaft 6 rotates in a first rotational direction when the drive pistons move towards one another and in a second rotational direction when the drive pistons move away from one another. As an alternative to the arrangement consisting of toothed racks and driven pinion gear, a tumbler yoke (Scotch yoke) can also be used to convert the linear movement of the drive piston arrangement 19 into a rotational movement of the driven shaft 6.

(23) FIG. 3 shows an exploded illustration of the rotary drive 40. As shown in FIG. 3, a receiving chamber 38 is provided in the wall section 35 of the housing 1, into which the sensor module 36 is inserted. The receiving chamber 38 is open towards a face side 3 of the housing 1. The sensor module 36 in the inserted state can be covered by a housing cover and held in the receiving chamber 38.

(24) FIGS. 4 and 5 show perspective illustrations of a rotary drive 50 according to a second embodiment.

(25) The second embodiment differs from the first embodiment in particular in that, in the second embodiment, a sensor module 37 is provided which is arranged on the housing 1 such that it can be removed and is not, as in the first embodiment, arranged in a wall section of the housing.

(26) Furthermore, in the second embodiment the control device is preferably provided separate from the sensor module 37 in or on the housing 1. For example, the control device can be arranged in a function module arrangement attached to the face side 3 of the housing 1.

(27) In the second embodiment, the control device is designed to determine, on the basis of whether valid magnetic field measurement values are received at the control device or whether any magnetic field measurement values at all are received from the sensor element at the control device, whether the sensor module 37 is being removed from the housing 1 or is being attached to it.

(28) By analogy with the above described embodiment, the control device is adapted to adopt an error state, if a removal of the sensor module 37 is determined, and to adopt a calibration state, if an attachment of the sensor module 37 is determined.

(29) As shown in FIG. 5, the sensor module 37 is preferably box-shaped and has a hollow space, in which the magnet module 23 is accommodated when the sensor module is attached to the housing 1.

(30) FIGS. 6 and 7 show the magnet module 23 adapted as a position indicator. As described above, the position indicator comprises a bracket-shaped indicating element 39 and the magnet arrangement 34 formed as a ring segment. Preferably, the magnetisation of the magnet arrangement 34 varies along the circumference of the ring segment.

(31) FIG. 8 shows a process valve assembly 60 according to a third embodiment. In the example shown, the process valve assembly 60 comprises a rotary drive 40 according to the first embodiment. As an alternative to this, the process valve assembly 60 can also comprise a rotary drive 50 according to the second embodiment.

(32) The rotary drive 40 sits on a valve fitting 24 which has a spindle and a valve element. The driven shaft 6 is connected in a torque-proof manner to the valve element of the valve fitting 24 via the spindle. The angular position of the valve element is correspondingly determined from the angular position of the driven shaft 6. As a consequence, the position of the valve element can be derived from a position signal provided by the sensor module 36 or the control device and corresponding to the position of the driven shaft 6.

(33) In operation, the process valve assembly 60 is provided with compressed air from a line connected to an external pressure connection of the rotary drive 40. The compressed air is, for example, drawn through a control valve arrangement (not shown here) which is preferably provided in a function module arrangement attached to the face side 3 of the housing 1 and is in particular designed as a 5-port/3-way valve. The outputs of the control valve arrangement are connected to chambers of the piston space 11 via corresponding working channels. The outputs of the control valve arrangement are switched to a pressure state or ventilation state according to a control command, in order to keep the drive pistons of the drive piston arrangement 19 in their current position or in a defined position or move them towards one another or away from one another. The control command is, for example, issued by the control device or another control unit assigned to the rotary drive. The driven shaft 6 is rotated by the movement of the drive pistons of the drive piston arrangement 19, whereby, in turn, the spindle of the valve fitting 24 and finally the valve element of the valve fitting 24 are rotated or actuated.

(34) The magnet module connected to the driven shaft 6 in a torque-proof manner receives the rotational movement of the driven shaft 6, so that the location or position of the magnet arrangement 34 relative to the sensor module 36 is altered. Correspondingly, the magnetic field sensor value detected by the sensor module also changes. The position of the driven shaft 6 is determined based on the detected magnetic field sensor value. In addition, the control device determines, according to the magnetic field sensor value, whether the magnet module 23 is removed from the driven shaft 6 or is attached to it and correspondingly adopts an error state or a calibration state.