FI104997B - Device for controlling the position of an operating device - Google Patents

Description

104997

INSTITUTION REGULATORY APPLIANCE

The invention relates to the application of force and motion to a valve stem or similar actuator from a motion generating device, preferably an electric motor, so that the motor and the required gearbox are as narrow as possible and: the position of the actuator is accurate and its position accurately measured.

From WO 92/13996 an electric motor / gear arrangement is known to effect such movement as a position adjusting unit. In the device according to the publication, the motor rotates the nut part on the output shaft by means of a worm gear, thereby rotating. Inside the nut part is a non-rotatable output shaft with a screw part, which consequently produces an axial movement. Measuring axial movement from the output shaft is tricky, whereby a solution is implemented in which the axial movement inside the housing is transferred by means of a separate delicate rod to a suitable linear motion detector. Such a procedure is also used in similar devices where rotary movement is induced on the output shaft. By means of a screw and a nut, a separate axial movement proportional to the rotation movement is obtained, e.g. for the linear sensor only, so that it can be used in this case also for measuring the rotation movement.

The disadvantage of the solutions is that the movement of the output shaft, be it rotational or axial movement, is not measured by the sensor directly from the axis itself, but by movement of the rods to the sensor or by means of a screw and nut into axial movement. The measuring sensor is often attached to a body part of the device which is not the actual mounting body of the device to the substrate in use. These * issues diminish the accuracy of the measurements due to clearances, thermal expansion and mechanical wear.

The invention is characterized by what is stated in the claims.

2,104,997

An advantage of the present invention is that the sensor measuring the angular position of the actuator is provided inside the housing and can nevertheless measure the rotation of the output shaft of the apparatus from the shaft itself. While the sensor is still supported on the body portion of the device that secures the device to the base, the sensor can measure the rotation of the output shaft without distraction. The measurement result transmitted by the sensor is »offset with respect to the output shaft. The electronically implemented non-contact angle sensor further has the advantage of offsetting the sensor, which eliminates the effect of possible axial movement on the output shaft on the sensor measurement result.

In the following, the invention will be explained in more detail with reference to the accompanying drawing, in which

Figure 1 is a side elevational view of a device according to the invention having a rotatable element as an outlet.

Fig. 2 is an end view of the device.

Figure 3 is a side elevational view of the angle sensor.

Figure 4 shows an oblique view of the angle sensor.

Figure 1 illustrates an embodiment of the invention in which, for example, a spindle valve spindle is provided with a precisely controlled rotational movement via element 8. The device shown in Fig. 1 generates a controlled rotation and measures its magnitude. The measurement result can also be retrieved from the device as a standard message, if necessary, so that it can be utilized e.g.

The motor 2 rotates the gearbox 3, which is e.g. a planetary gear, an epicyclic gear, etc. The gearbox drops the rotational speed while increasing the torque. The rotational movement is transmitted from the gearbox along the shaft 6 to the output shaft 8, between which there is a lock. An angular sensor 5 for measuring rotational movement is disposed about the output shaft 8, further comprising a base bearing 18, which in the example is a sliding bearing, a shaft seal 10, and a shaft 9 indicating rotation of the shaft. groove to frame 7.

3, 104997

At the end of the shaft 8 there is an adapter for transmitting the rotational movement to the valve stem. Valve spindle not shown.

Figure 3 shows an electronically non-contact sensor type that measures an angular position. The sensor 5 comprises a fixed first portion 12, which is preferably a plate, to be attached to the body part 7. Further, the sensor includes a second shaft-rotating part 11,13,14 which is to be mounted on the shaft 8. The second portion consists of a sleeve 14 as well as a pair of sensor plates 11 and 13. The sensor plates are attached to the sleeve 14 at a distance from each other such that the plate 12 is spaced between them without contact.

Figure 4 shows the structure of the sensor 5. The sensor plates 11 and 13 are half plates and the plate 12 is a disc having a surface on each side are formed piirilevyrakenteena the electrically conductive pattern arrangement 16. The circuit board is a three-wire control unit 4. From the control unit is sent to the stimuli to the sensor 5, and due to the portions 12 and 11,13 mutual angular position sensor signal varies. The sensor plate 13 is located below the plate 12, thereby compensating for the effect of any slight pivoting of the shaft 8 on the sensor result. No large dorsal movement is allowed since plate 12 is not very spaced between plates 11,13 in the sensor. No space is allowed between these parts until contact. The plate 12 has fastening holes 19.

The measurement principle of the transducer 5 may be the measurement of variable capacitance, # inductance or magnetic field with portions 12 and 11,13 rotating relative to each other. The angle of rotation to be measured is preferably less than 180 °. The output of the sensor is the ratio of the measurement results of the two halves, suitably modified (4..20 mA; 1 ... 5 V or other suitable for the application). If the sensor measures inductance, the output is proportional to the board; 12, the left-side inductor pattern with the correct Def len inductance of FIG. The ratio changes as the plates 11,13 rotate relative to the plate 12. This principle is also present in a capacitance or magnetic field sensor.

If arm 9 is not needed to limit rotation of shaft 8, it may be located as a pointer arm at the very end of shaft 8 or mounted e.g.

Claims (5)

A device which adjusts the position of an activator, as well as a valve stem or a control lip or a cladding egg in a paper machine, to which the device includes a fastening frame (7) for mounting the device, an adjusting element of the actuator position and acting as a recess (8) movable with respect to the mounting frame, a motor (2) providing rotation for said element and a gear (3), a sensor (5) measuring and identifying the angular position of the activator and an electronic control unit (4), (5) is a contactless electronic sensor, the movable first portion (12) of which is fixedly fixed in the movable mounting frame (7) of the device and the second portion (11,13,14) which moves contactless in respect of the preceding portion is fixed rigidly in the rotating element (8), characterized in that the element (8) is adapted to an axis which transmits rotation through the sensor (5) and that the sensor lies on the part of the axis which is acts into the protective cap of the device (1). 2. Apparatus according to claim 1, characterized in that the angle sensor (5) is a plane coil whose electrical properties receive change as the first (12) and second part (13) of the sensor rotate with respect to each other. 3. Device according to claim 1. "that the angle sensor indicates whether the magnetic field or inductance changes in the sensor when the sensor's first (129 and second portion (13) rotates in respect of each other). 4. Device according to any one of the preceding claims 1-3, characterized in that the extending element rotates not more than 180 ". Device according to any one of the preceding claims 1-4, characterized in that, as a recess, the adjusting element (8) acts as a uniform shaft, in which shaft is attached or with which shaft is in contact as seen from the inside of the device: the second part of the sensor (13). , 14), a frame bearing (18), shaft seal (10) and a pointer (9) indicating the rotation of the shaft.