Abstract:
An electromagnetic control motor device, particularly a ratio metre is disclosed, of the type including: a control coil assembly (10, 20), a frame (50) for supporting the coil assembly (10, 20), a magnet device rotatably driven by said control coil assembly (10, 20) and a magnetic shield (100) surrounding at least partially the coil assembly (10, 20) and support frame, characterised in that said shield (100) has an annular non-right cylindrical skirt (110).
Abstract:
Fluid thrust bearing containing moving magnet indicating instrument (10) includes a bobbin (12) and transparent lens (14) through which pointer (16) and dial (18) can be viewed. Pointer (16) is mounted to end of shaft (20) having axis of revolution (28) and attached to rotor (30) in bore (34). The rotor (30) is disposed in close-fitting walled cavity (26) so as to define a small substantially air excluded damping fluid filled gap (32) therebetween. Shown near detail arrows (1A) are excess fluid containing reservoir (33) formed by raised torroidal ridges (36, 38). Indicator (10) contains two pairs of field coils (22.1, 22.2, 24.1, 24.2). Adhesion and cohesion help maintain the rotor (30) in cavity (26). The substantial air exclusion helps prevent rotor (30) from moving axially out of cavity (26). A method of assembling to create such conditions therein is also set forth.
Abstract:
The invention relates to a method for positioning a pointer of an indicator device, especially of a combined instrument in an automobile. Said pointer can be positioned on a scale by means of an electronically controlled stepper motor (16). According to the invention, an actual position (30) of the pointer (12) is scanned when the voltage supply for the display device (10) is switched on and the pointer (30) is only moved into the starting position (28) by means of the stepper motor (16) performing an initialisation run if said actual position (30) is different from said starting position (28).
Abstract:
A stepping motor-type instrument (6) having drive circuits (3, 4) for driving a stepping motor based on digital signals corresponding to a measured quantity, wherein a needle (9) attached to an end of a drive shaft of the stepping motor indicates a scale (8) on a dial (7) corresponding to the measured quantity. The stepping motor-type instrument (6) comprises a processing means (3) which receives digital signals corresponding to the measured quantity and converts them into an indication angle data at a predetermined period, and a delay means (4) which finds a difference between a preceeding indication angle data and a succeeding indication angle data that are consecutively output from the processing means (3) at a period of conversion, and, when the difference is larger than a predetermined value, converts the signals so that the difference becomes smaller than the predetermined value to output the converted signals as continuous indication angle data. This prevents step-out and makes it possible to reliably follow up a change in the quantity of measurement.
Abstract:
A process is disclosed for correcting a non-linear relation between the electric phase angle and the mechanical output angle of step motors by using a low resolution encoder or the like. This process represents a compromise between the classical regulation of step motors, that requires a high resolution angle detection, and a purely statistical correction of the characteristic curve. The result is a substantial synchronism improvement, for example when conventional claw pole step motors are used for driving the pointer of a display in a motor vehicle. The micro-step control is carried out with a corrected sine wave form. Coefficients evaluated by simplified Fourier synthesis are essentially used to correct the sine wave form.
Abstract:
A movable magnet type measuring instrument capable of suppressing, with a reduced cost, the leakage of damper oil while reducing an effect on the operating characteristics of a needle, comprising a magnet rotor (2) having a rotating shaft (1), a frame body (4) having a hollow part (3) for storing the magnet rotor (2) and supporting the rotating shaft (1), coils (5, 6) disposed on the outer periphery of the frame body (4) and driving the magnet rotor (2), and damper oil (D) contained in the hollow part (3), wherein a rough surface part (S) for suppressing the movement of the damper oil (D) is provided on at least either of the outer wall surface (21) of the magnet rotor (2) and the inner wall surface (31) of the hollow part (3).
Abstract:
A miniature crossed coil gauge (30) having an oriented rare earth magnet (40) fixedly mounted on a rotary shaft (38) supplying a magnetic flux directed transverse to the shaft axis. The gauge housing provided by upper (32) and lower (34) bobbins surrounds the magnet and supports the shaft. First (42) and second (44) coils are wound about the gauge housing in a crossed coil orientation encircling the magnet. A flux ring (50) is disposed around the first (42) and second (44) coils axially aligned with respect to the magnet (40). The magnet (40) has sufficient strength and the flux ring (50) is mounted in sufficiently close to the first and second coils to redistribute flux supplied by the magnet so that magnetic flux measured at the surface of the coils is substantially increased relative to the magnetic flux density measured with the flux ring removed. This gauge construction facilitates fabrication of gauges so small that they can be directly mounted on printed circuit boards using conventional electronic component mounting equipment.
Abstract:
The invention concerns a mechanical indicator with electric control comprising drive windings (50), in particular of logometer type, comprising a control device including means for generating control electric signals applied to the windings. The invention is characterised in that the control means comprise a filter (12) receiving the input signal to be displayed, comparing means (13) for comparing the signal levels in the filter (12) input and output, and means (13-18) for superposing an alternative component on the filter (12) output signal, to generate a vibration of the indicator (50) moving element when the variation between the signal levels in the filter (12) input and output becomes less than a predetermined threshold.
Abstract:
Moving magnet indicating instruments in which a damping fluid migration barrier (74) projects from the inside of one wall of the bobbin coil (61) and another damping fluid migration barrier (68) projects from the face of the rotor (62) which confronts that wall.