RU1768951C - Digital angle-of-turn transducer - Google Patents

Abstract

The invention relates to measuring technique and is aimed at improving the accuracy of a discrete angle-of-rotation transducer by reducing the effect on the measurement result of the axial displacements of the rotor 1, which is connected with the test object during the measurement process. The transducer contains a magnetic system made in the form of a C-shaped magnetic core 3, on which permanent magnets 4 are fixed, a U-shaped hub 5 and a Hall element 6 located on the middle shaft of the hub 5, and a rotor 1 with ferromagnetic inserts 2 evenly spaced its circumference. In this case, the angular distance between the inserts is equal to the angular distance between the central and lateral protrusions of the hub 5, the ends of which are bounded by portions of the side surface of the ring having an average radius equal to The radius of the circle along which are arranged the insert 2. In this size ratio of the converter output signal in its level there, are independent of conductive axial displacement of the rotor 5 yl CO C

Description

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FIELD OF THE INVENTION This invention relates to measuring and control equipment, and can be used in automation, robotics, and mechanical engineering.

A rotation angle converter is known which consists of a rotor, a permanent magnet and a Hall converter. The rotor comprises openings whose centers are located around the circumference and at the same distance from each other. A permanent magnet is located on one side, and a Hall converter on the other. The disadvantages of this transducer include the occurrence of eddy currents in the ferromagnetic rotor and significant scattering magnetic fluxes, as well as the fact that the error in determining the discrete rotation angle depends significantly on the axial displacements of the rotor, which is its disadvantage.

Closest to this invention is a discrete angle transducer, which contains a C-shaped magnetic core placed at its ends one opposite the other, a permanent magnet and a magnetic field concentrator, a Hall element mounted on the hub and installed in the gap between the magnet and the hub, a disk rotor made of non-magnetic material and having through holes evenly spaced along its circumference with ferromagnetic inserts filling them, The disadvantage of this transformation The spindle angle is a significant error in the measurement of the discrete angle of rotation due to random axial displacements of the rotor.

The purpose of the invention is to improve the accuracy of a discrete angle transducer.

This is achieved by the fact that in the angle-angle transducer containing a C-shaped magnetic core, a permanent magnet and a magnetic field concentrator are placed at its ends opposite one another, a Hall element is mounted on the concentrator and a disk rotor made of non-magnetic mounted in the gap between the magnet and the concentrator material and having through holes evenly spaced along its circumference with ferromagnetic inserts filling them, and the magnetic field concentrator is made in the form of a W-shaped magnetic ode, the protrusions are limited portions of the side surface of the ring having a mean radius equal to the radius of the circle on which the openings are arranged on the rotor, the Hall element fixed to

the middle protrusion of the concentrator, and the angular distance between the ferromagnetic inserts in the holes of the rotor is equal to the angular distance between the lateral protrusions

hub.

Figure 1 shows a diagram of a device; figure 2 is a section aa in figure 1; on figs and 4-two projections of the W-shaped hub; Fig. 5 is a graph of the dependence of the output signal of the Hall converter on the rotation angle in the absence of axial displacements of the rotor (curve 1) and with axial displacements of the rotor of the opposite sign (curves 2,3).

5 The discrete angle-of-rotation converter includes a rotor 1 of non-magnetic and non-conductive material containing ferromagnetic inserts 2 a C-shaped magnetic core 3 with two constant magnetic

0 filaments 4, a W-shaped concentrator 5, on the middle protrusion of which a Hall transducer 6 is located. Permanent magnets 4 are oriented in the directions of magnetization parallel to each other and parallel to the axis of rotation of the rotor. The centers of the protrusions of the hub 5 and the ferromagnetic inserts 2 of the rotor 1 are located on a circle of the same radius. The centers of the circles are located on one straight line, which is perpendicular to the planes containing them.

Discrete angle transducer operates as follows. When the rotor rotates, there is a periodic change in the magnetic flux passing through the middle protrusion of the W-shaped concentrator 5. Consequently, a periodic dependence of the output signal U of the Hall transducer 6 on the angle

0 p rotation, shown in Fig.5 (curve 1). The maxima in the dependence U (p) are observed when the ferromagnetic inserts 2 are located against the middle protrusion of the concentrator 5. According to the signal U equal to Uc,

5, the rotation angle is determined. The operating voltage Uc is selected such that the angle of rotation po at which U Uc is equal to the angle of rotation at which U Uc. The angle of rotation is

0p

ro - (n is the number of ferromagnetic inserts

2). The magnitude of the maxima of the dependence U p is determined by the gap between the concentrator 5 and the rotor 1, which can change 5 due to random axial displacements of the rotor. Due to the fact that the angular distance between the ferromagnetic inserts 2 is equal to the angular distance between the side protrusions of the concentrator, the maxima decrease with an increase in the gap.

and the minima increase, as can be seen from Fig. 5 (curve 2). Conversely, if the clearance decreases, the maxima increase and the minima decrease (curve 3 in Fig. 5). In this case, curves 1,2 and 3 intersect at points corresponding to the angle p0, 2 p0, 3 (p0, etc., and the operating voltage Uc. Thus, due to the use of a U-shaped hub, in which the centers of the protrusions and the centers of the ferromagnetic inserts in the rotor are located on a circle of the same radius, and the fact that the angular distance between the ferromagnetic inserts coincides with the angular distance between the side protrusions of the hub increases the accuracy of measuring the angle of rotation.

Claims (1)

SUMMARY OF THE INVENTION A discrete angle-of-angle transducer comprising a magnet-shaped conductor, one at its ends Riga from 4O 0 5 0 opposite to the other, a permanent magnet and a magnetic field capacitor, a Hall element fixed to the hub and installed in the gap between the magnet and the hub, a disk rotor made of non-magnetic material and having through holes evenly spaced along its circumference with ferromagnetic inserts filling them, characterized in that , in order to improve accuracy, the magnetic field concentrator is made in the form of a U-shaped magnetic conductor, the ends of the protrusions of which are limited by the sections of the side surface of the ring, Commercially median radius equal to the radius of the circle on which the openings are arranged on the rotor, the Hall element is mounted on the middle protrusion concentrator, and the angular distance between the ferromagnetic inserts in the openings of the rotor equal to the angular distance between the side protrusions concentrator.  figure 1 Y2% 3% Y FIG. 5