Abstract: A device for measuring rotary motion, preferably the rotational speed of the vehicle wheels, has a signal generator ring mounted on a wheel bearing outer ring which rotates with the wheel. A protective housing is mounted to a stationary member and surrounds the signal generator ring. A sensor which is snug-fittingly accommodated in a holder is fixed onto the stationary member by way of a flange on the protective housing. The holder holds and retains the sensor in the predetermined position on the periphery of the signal generator ring.

Abstract: A device for detection of the speed of rotation of a rolling bearing which has an encoder element mounted on the rotating part of the bearing and a sensor unit consisting of a sensor holder attached to a support mounted in contact with a nonrotating part of the bearing. The sensor unit is mounted on an elastic member for positioning with respect to the encoder element and may be adjusted with respect to a removable immobilization component of the sensor unit in contact with the support.

Abstract: A method of manufacturing a rotation sensor can effectively prevent a sensor element from moving during a resin molding process for forming a resin portion that covers the sensor element to provide excellent waterproofness and airtightness. During a first resin injection step, an end of a bobbin of the sensor element is fixed or held in place by a slide core. Thereafter the slide core is extracted and resin is again injected in a second injection step into a vacated portion that is formed by extraction of the slide core. In the finished rotation sensor, the resin completely surrounds and encloses the bobbin, except at an exposed end of a magnetic pole piece. A metal mounting bracket is embedded in the resin at a spacing away from the bobbin. The bobbin has a positioning cavity to receive the slide core during the molding. The resin covering an upper part of the bobbin is at least four times as thick as the resin covering the coil of the sensor element.

Abstract: A sensor for detecting the angular velocity of a rotating member. The sensor includes a bobbin having an exterior defining an annular recess and a coil within the recess. The bobbin also has a generally cylindrical aperture and supports a probe and a permanent magnet in the aperture. The housing is secured to the bobbin and the housing and bobbin include tapered inner and outer surfaces, respectively, that are made to form a wedge fit seal between the bobbin and the housing to prevent the introduction of molding material during the overmolding process. The bobbin also includes supports for supporting the lead wires extending between the coil and the terminals.

Abstract: A system for remotely starting a diesel engine of a vehicle. The system comprises a portable hand-held RF transmitter issuing a command in the form of a binary-coded sequence. A slave controller mounted on-board the vehicle executes the command by energizing the starter motor in order to crank and start-up the diesel engine. The system includes a Hall-effect sensor responsive to the pulsating magnetic field of the diesel engine alternator for generating a signal indicative of the rotational speed of the engine. The slave controller uses this information for detecting when the engine has been successfully started in order to de-energize the starter motor.

Abstract: In an arrangement for fastening an annular member on a hub member, wherein the annular member (1) has a locking tab (14) formed on its inner surface which engages in an annular locking groove (13) formed on the outer circumference of the hub member (2). The annular member (1) is provided with a radially extending wing tab (8) for fixing non-rotatably to the hub member (2).

Abstract: A bearing with integrated data sensor has a stationary bearing ring, a rotatable bearing ring, and rolling elements in contact with the bearing rings. An encoder is mounted on the rotatable bearing ring, and a sealing gasket is mounted on the stationary bearing ring. A sleeve for protection of a sensor cable is integrally connected to the sealing gasket and has a groove for housing a sensor means which is connected to the sensor cable. The sleeve has a wall of its extremity which is substantially perpendicular to an external side of the sealing gasket through which the sensor cable exits such that it is tangential to said external side of the sealing gasket.

Abstract: A test device for vehicles has a wheel rotation speed sensor which is sensitive to magnetic fields. The test device, having a wheel rotation simulation device, contains a sensor stimulating magnet coil, which can be positioned in the magnetic field region of the sensor such that a magnetic field coupling is provided. A control unit, drives this magnet coil with an AC voltage at a frequency which determines the wheel rotation speed. This allows the performance of functional tests of components which are sensitive to wheel rotation speed while keeping the wheels stationary. In addition, a compact roller unit, which is preferably transportable, is provided in order to carry out actual wheel rotations in order to make it possible to test further components, such as the brake system or electronic transmission control.

Abstract: A mechanism for the attachment of a speed sensor to a vehicle comprising a rotary body for attachment to an end of a wheel axle such that the rotary body rotates with the wheel axle, the rotary body having an outer peripheral surface, the outer peripheral surface having a gear wheel with teeth; a sensor mounting body within which the rotary body rotates by means of a bearing therebetween; a speed sensor attached to the sensor mounting body and aligned opposite to the gear wheel with teeth of the rotary body, the bearing maintaining a predetermined gap between the speed sensor and the gear wheel with teeth, the teeth providing the change in magnetic field sensed by the speed sensor when the rotary body is rotating with the wheel axle so that the speed sensor generates a signal corresponding to the rotational speed of the wheel axle; and a connection link through which the sensor mounting body is connected to a frame of the vehicle.

Abstract: An adaptive threshold circuit for use with a magnetic type of sensor that has a pick-up coil. The pick-up coil has an alternating voltage induced therein when a slot or tooth formed in a wheel rotates past the sensor. The circuit produces a square wave pulse voltage during positive half-cycles of the voltage generated in the pick-up coil. The circuit includes a digital to analog converter the input of which is connected to a selectable pulse counter. The pulse counter has a decrement function that allows for the count to be varied so as to accommodate sudden wheel decelerations. According to one embodiment, the counter may down count to reduce the count number. In accordance with a second embodiment, the counter may shift out one bit to perform a divide-by-two operation on the count number.

Abstract: A device for measuring rotation which is mounted into a wheel bearing. The device is substantially composed of a transducer arranged around the axis or rotation of the part performing the rotation, and of a signal generator ring which is part of a hollow-cylindrical or bowl-shaped signal generator component part. The signal generator ring is supported rotatably on a cylindrical part of the transducer.

Abstract: An inductive sensor (11) with an electric coil (14) cooperates with a revolving, magnetically conducting part to produce electric signals. The ends of the windings of the coil (14) are wound on at one end (21) of a conductor bar (15). A securing bracket (31) is punched out of the conductor bar (15) so that the bent end (21) of the conductor bar can be fastened and the securing bracket (31) also presses on the bent end (21). In this way, the end (21) of the conductor bar is securely fastened and cannot be detached in particular during a change in temperature. This improves the durability of the sensor (11 ).

Abstract: A rotary speed measurement device includes an oscillator including a resonant circuit with a coil which conducts a resonant current to develop a magnetic field therearound. A wheel is connected to rotate together with a rotating member and is provided along circumference with alternately arranged first and second marks which causes different magnetic effect on the magnetic field. The coil is disposed adjacent the wheel so as to sense the magnetic effect and provide a corresponding voltage Vs. An analyzer is provided to give a parameter Vsub based upon voltage Vs and to compare the parameter with a predetermined threshold V.sub.TH to give a pulse when the parameter exceeds the threshold as indicative of that the wheel rotates by an increment corresponding to an angular distance between the first mark and the adjacent second mark. The pulse is counted by a counter within a unit time to obtain a rotary speed of the wheel.

Abstract: A wheel speed sensing device with shape-coupled sensor and exciter ring components reduces the effects of tolerance stack variances in the relative radial and axial locations of the sensor and exciter ring. Additionally, the assembly is readily adapted to installation within the sealed confines of the bearing area of a wheel.

Abstract: Apparatus for determining the rotational speed of an AC induction motor based on a spectrum analysis of a magnetic flux signal. For a Phase I analysis, which is usually sufficient, three sets of families of peaks indicative of possible rotational speeds are defined, and the flux frequency spectrum is searched for peaks meeting the family definitions to determine candidate speeds, and to assign scores. If there is a candidate speed with an overall score which exceeds a predetermined threshold, the motor rotational speed is determined as that candidate speed. A Phase II analysis, employing a more exhaustive set of five additional family definitions, is applied when Phase I fails to reach a result.

Abstract: A speed signal conditioning and test circuit includes a comparator which is connected to a digital input port of a microprocessor and which switches its output in response to the alternating current generated by the sensor when sensing wheel speed. A test sequence is initiated by injecting a signal into a tuned circuit formed by the inductance of the sensor coil, the filtering capacitors, and associated circuit resistances. The voltage output of the tuned circuit increases exponentially and switches the comparator to provide a test pulse of a predetermined time period. The microprocessor times the pulse to establish that an operative sensor is present. Since the inductance of the coil is switched out of the circuit in the case of an open or shorted sensor coil, no pulse is generated and the microprocessor accordingly determines that a defective sensor is present.

Abstract: A wheel speed sensor input circuit with sensor status detection having a comparator with a first input and a second input where both the first and second inputs are connected to a wheel speed sensor having electrical resistance where, when the status of the wheel speed sensor is to be ascertained, the second input is connected to ground through a diode using a switching transistor and the output of the comparator is driven high or low depending on the speed sensor electrical resistance where the output is high if the speed sensor is operational.

Abstract: Apparatus is presented for controlling the duty cycle of a pulse generator which provides a periodic input signal having a frequency proportional to the rate of movement of an input member. The input signal is compared with a threshold signal and, for each cycle of the periodic signal, an ON signal is provided so long as the magnitude of the input signal exceeds that of the threshold signal. The apparatus for controlling the duty cycle includes a clock source for providing clock pulses having a fixed frequency rate. A first counter counts the total number of clock pulses occurring during an interval corresponding with N of the ON pulses to provide a total count of B. A second counter counts the total number of clock pulses occurring during each of the N ON pulses and provide a total count of A. The ratio of A to B is calculated to provide a ratio R.

Abstract: In accordance with the teachings of the present invention, a fault detection circuit is provided which detects short circuits on differential leads associated with a magnetic sensor and modifies said differential voltage to avoid possible errors associated with a short circuit. The circuit includes a first and second input coupled to first and second signal lines for receiving a differential voltage. A first voltage comparator compares voltage potentials at the first and second signal lines so as to detect equal voltage crossings and provide an output in response thereto. A rectifier is coupled to the first and second signal lines in the output of the first comparator and has first and second outputs for producing positive half-wave voltage cycles with a voltage potential at each of the first and second lead lines. A second comparator is provided for comparing the half-wave voltage cycles with a first threshold voltage that represents a short circuit power source.

Abstract: The inductive sensor has an electrical coil (14) having winding end portions (114) and current conductors (15) having conductor end portions (115) which are electrically contacted by the winding end portions (114) of the coil in a contact region (18) in the sensor housing (10). A permanently elastic material (26), advantageously silicone, encloses the contact region (18) between the conductor end portions (115) and the winding end portions (114). A temperature-resistant circumferential element (28) bearing on the housing (10) also encloses the contact region (18). This circumferential element (28) can be a polyimide strip or heat-resistant adhesive tape. This inductive sensor allows temperature fluctuation cycles to be increased by up to four times without damaging the coil wire and improves sensor durability.

Abstract: A variable reluctance magnetic transducer including a tubular housing having a closed end and an open end. A bracket is attached to the outside of the housing a predetermined distance form the closed end of the housing. A core supporting a ferrous metal pole piece and a permanent magnet is disposed within the housing with an end of the pole piece contacting the inside of the closed end of the housing to accurately position the pole piece end relative to the bracket. The core supports a pair of fork terminals which engage arcuate blade terminals carried by a cap assembly. The blade terminals allow positioning of the cap assembly at a plurality of angles relative to the core and housing.

Abstract: A magnetic field alternation detecting apparatus includes a magnetic member sensor enclosed in a case and having a core (i.e., a yoke) to which a magnet is attached and around which a coil is wound. The magnetic member sensor obtains as an electromotive voltage a change in magnetic flux linking the coil on the basis of a magnetic field distribution disturbed by an approaching magnetic member present near the case from a pair of output terminals of the coil. An analog-to-digital converter is connected to the output terminals of the coil using at least one control terminal of a transistor such as a bipolar transistor or an enhancement operation field effect transistor. A main current terminal of the transistor is connected to a pair of output terminals.

Abstract: An anti-lock brake system includes a relatively low cost, toothed ring for sensing vehicle speed. The toothed ring can be molded out of an elastomeric material containing finely divided particulates that are magnetically permeable. The molded, toothed ring includes magnetically permeable projecting teeth which magnetically interact with a magnetic field generated in a speed sensor to provide a pulsating voltage related to vehicle wheel speed. The toothed ring can be an integral part of an oil seal or wear sleeve positioned between a vehicle axle and wheel hub.

Abstract: The present invention provides a generally contactless method and apparatus for producing a speed reference for a rail vehicle which amenable to retrofit applications. The invention utilizes a laser source to direct a laser beam on a portion of the wheel and axle assembly of the rail vehicle. In presently preferred embodiments, the laser beam is directed on a tread or flange section of the vehicle wheel. The laser beam is believed to excite the molecules on the surface of the wheel in such a way that magnetic susceptibility is significantly increased. The increased magnetic susceptibility facilitates encoding of a magnetic signal by a magnetic encoding head. This magnetic signal may then be received after further rotation of the wheel by an angularly displaced magnetic receiving head. Processing circuitry is electrically connected to the magnetic encoding head and the magnetic receiving head to derive the speed reference based on the angular velocity and dimensions of the wheel.

Abstract: A stationary bearing ring, a rotatable bearing ring, and a sensor support having a slide are provided. The sensor support is axially retained in engagement with the stationary bearing ring, and a sensor is slidably mounted in the slide of the sensor support. The sensor is biased into contact with the sensor support and is radially retained in the slide. An encoding element is carried by the rotatable bearing ring and is rotatable in front of the sensor. Various embodiments are disclosed.

Abstract: A speed and/or distance transducer is mounted in a bolt-shaped hollow housing and is threaded into a transmission and locked in place with its detector and adjacent a toothed wheel which rotates to produce an electrical output. An indicia is provided on the head of the bolt to allow proper spacing of the end of the transducer relative to the toothed wheel. A divider converts the output of the detector and a switch with a rotary member can be accessed through a bolt opening to allow the divider ratio to be changed. A plug covers the opening after the dividing ratio has been selected.

Abstract: An adaptive loading circuit is provided for adaptively attenuating an alternating differential voltage that is produced by a magnetic sensor in response to the rotation of a wheel while maintaining noise immunity. The circuit includes an input for receiving an input differential voltage from the magnetic sensor via first and second input lines. A resistive divider network is included which has a resistive load serially connected to each of the first and second input lines and a plurality of adaptively selectable parallel resistive loads connected between the first and second input lines. Combinations of the parallel resistive loads are adaptively selected when the input differential voltage exceeds predetermined voltage thresholds so as to divide the input differential voltage into a selected portion thereof as an output differential voltage. In addition, the parallel resistive loads may be selectively switched out when the input differential voltage drops below a low voltage threshold.

Abstract: A reluctance sensor produces reluctance signals in response to passing slots in a rotating wheel. When a given signal exceeds a threshold, a DIG.sub.-- OUT signal is produced. When the signal falls to zero, the DIG.sub.-- OUT signal is terminated. The invention adjusts the threshold, based on the magnitude of the reluctance signals. Since the magnitude of the reluctance signals depends on wheel speed, the invention, in effect, adjusts the threshold based on wheel speed, yet without independently measuring wheel speed.

Abstract: A device for sensing the rotation speed of a bearing comprises an encoder member fastened to a rotating part of the bearing and a sensor assembly comprising a plastics material sensor support housing a sensor and a metal support for locating and fastening the sensor assembly on and to a non-rotating part of the bearing. The sensor support is overmolded onto the latter's outside surface. The sensor faces the encoder member in order to measure its rotation speed. The-metal support comprises a substantially axial centring portion adapted to cooperate removably with a bearing surface on the non-rotating part of the bearing and a washer-like plane radial portion adjacent the centring portion adapted to be clamped between a radial surface of the non-rotating part of the bearing and a radial surface of a non-rotating member. The device may be fitted to vehicle wheel hub assemblies.

Abstract: An air gap detector for use in antilocking brake systems includes an active integrator that integrates an output signal from a wheel speed sensor, that depends in part on the relative spacing between the wheel axle and its associated bearing, to thereby produce a signal that is inversely proportional to the air gap between the axle and bearing. The integrated signal is processed by peak detecting means to produce a peak signal that is proportional to the size of the air gap. The peak signal is then amplified and adjusted to produce a D.C. signal that is proportional to the size of the air gap.

Abstract: A detector for detecting the rotating speed of a wheel bearing having a pulser ring mounted between bearing rings of a wheel bearing at one end thereof. One of the bearing rings is adapted to rotate together with a wheel and the other is fixed. A ring is provided axially outside of the pulser ring and press-fitted on the fixed bearing ring. A rotating speed sensor is mounted on the ring and has a detecting portion inserted in a hole formed in the ring. A seal member is provided in the space between the ring and the rotatable bearing ring to seal the space. In another arrangement, the ring is mounted on the fixed one of the bearing rings and the detected portion of the pulser ring is located opposite to the detecting portion of the rotating speed sensor with a radial gap defined therebetween.

Abstract: A rolling bearing unit for sensing rotational speed has a synthetic resin connector to which a plug is connected to output a signal from a senser, and a metal cover lot supporting and protecting the connector.

Abstract: A sensor having a wide sensing range is capable of being controll by a small scale processor. The sensor comprises: a plurality of planar zigzag coils being provided on substrates, the planar zigzag coils having the same coil pitch and being formed into zigzag shape in a first direction, the planar zigzag coils being capable of relative movement in the first direction, the planar zigzag coils including a first planar zigzag coil, which is a primary coil, and a second planar zigzag coil, which is a secondary coil; a magnetizing unit for magnetizing the first planar zigzag coil; a first detecting unit for detecting induced electromotive force, which is induced in the second planar zigzag coil by the first magnetized planar zigzag coil; and a second detecting unit for detecting displacement length between the first planar zigzag coil and the second planar zigzag coil on the basis of the induced electromotive force in the second planar zigzag coil.

Abstract: In a device for positional fixation of a coil support in a cup-shaped formed casing part, wherein a closure part (4, 8) is attached to the cup-shaped casing part (1, 2, 22). Said closure part (4, 8) is disposed on the side of the coil support (10, 19, 21) , located remotely relative to the floor (22) of the cup-shaped casing part (1, 2, 22), in or, respectively, at the cup-shaped casing part (1, 2, 22). Tongue-shaped adjuncts (9, 33) are furnished at the closure part (4, 8). Said tongue-shaped adjuncts (9, 33) extend in a direction toward the coil support (10, 19, 21) and exhibit nose-shaped protrusions (13, 29) directed toward the wall of the coil support (10, 19, 21) . Projections (11, 31) or, respectively, recesses (12, 30), are formed like a lock toothing, and are furnished at the coil and are disposed toward the tongue-shaped adjuncts (9, 33).

Abstract: A movement detector device consumes less power and provides a high detection reliability. The teeth on a rotating gear are magnetically detected. There are a number of interconnected magneto-resistors MR1 through MRi connected in series, with the series circuit connected between a power supply line and a ground line. There are output signal pickup points P1 through P7 at the connections between the adjacent magneto-resistors. Signals outputted from these signal pickup points P1 through P7 are shifted in their phases by 1/2period with respect to each other. These signals are paired, and each of the paired signals is fed to a differential amplifier circuit to provide signals E1 through E4 as detection signals. In another embodiments, a linear member has a number of magnetic spots which may be detected in the same manner that the gear teeth are detected.

Abstract: The retained magnetic strip has an elongated strip of magnetic material formed into a nearly circular band with an attaching, retaining, and protective ring of substantially rigid and non-magnetic material which encloses the magnetic strip.

Abstract: Device for sensing the rotational speed of a rotating element (4) mounted by means of a roller bearing on a non-rotating element (3), comprising a multipolar ring (17) which is integral with the rotating element, a sensor (19) which is made integral with the non-rotating element, and a magnetic flux concentrating means arranged in the immediate vicinity of the multipolar ring and cooperating with the sensor in order to concentrate and channel the magnetic flux emitted by the multipolar ring. The flux concentrating means is of annular shape and comprises at least a first end shield (24) having a radial part of which one circular edge is provided on its circumference with a sealing lip (25) intended for coming into contact directly or indirectly with the rotating element (4), and a second end shield (26) provided with radial teeth (27) spaced regularly along a circular path.

Abstract: A tachometer for monitoring the rotation of an output shaft (e.g. of a motor, where the motor is enclosed within a standard NEMA housing), includes an enclosure (e.g. adapted to be secured to an end plate of the motor housing), the enclosure having a radial center and a longitudinal axis which, when the enclosure is secured to the housing, are aligned with a longitudinal axis of the output shaft. The enclosure has at least one mounting surface in a peripheral wall portion thereof, the mounting surface having an aperture formed therein which opens in a radial direction. A sensor module including a pair of axially aligned magneto-resistive sensors is mountable on the mounting surface of the enclosure such that the module protrudes through the aperture with the sensors facing radially inwardly.

Abstract: A head for writing data into and/or reading data out of a recording medium such as a magnetic disc is displaced along a path by a motor such as a voice coil motor. The moving member of the motor is disposed on one side of the path, and another moving member of a speed sensor for detecting the head displacement speed is disposed on the opposite side. As a result, an unbalanced mass arrangement with respect to the path along which the head is displaced will not occur. The signal from the speed sensor can be used, for example, to interrupt a write operation if a mechanical impact occurs. Furthermore, even in an embodiment in which a coil is wound around the moving member of the speed sensor so that the head displacement speed is detected as a voltage induced across the coil as the head is displaced, the motor and the speed sensor are disposed in spaced-apart-relationship with each other and the speed sensor is less susceptible to adverse effects caused by the leakage flux from the motor.

Abstract: An RPM sensor for anti-lock and/or traction control systems of motor vehicles or for engine speed governing or gasoline or Diesel injection control. The RPM sensor has a housing, receiving electrical components, with a first housing part of plastic that is at least partly enveloped by a second housing part, produced in an injection molding process, likewise from plastic. To attain a moisture-proof, material bond between the two housing parts, a melting element of a plastic having a lower melting point than that of the plastic of the housing parts is disposed in a contact zone between the two housing parts. When the second housing part is formed, the melting element is heated above its melting point, and a material bond of the two housing parts is attained which protects the RPM sensor against moisture dirt, stress, etc.

Abstract: The invention comprises a velocity sensor (10, 30, 50, 60, 70, 110) that measures velocity in only one degree of freedom and is insensitive to the other five degrees of freedom. The velocity sensor uses differential flux splitting, and by sensing changes in flux, common mode effects are removed. In practising the invention, a permanent magnet (17, 33, 55, 65, 71, 131) is used to create a flux field, and multiple return paths are used to split the flux. A plurality of pole pieces (20-21, 39-40, 58-59, 66-67, 72-73, 111-112) simultaneously move an equal amount in relation to the return paths for differentially varying the amount of flux carried by each return path (13-14, 34-36, 52-53, 63-64, 73A-C and 75A-C, to thereby induce a differential voltage in secondary coils (15-16, 37-38, 56-57, 68-69, 80-83 and 90-93, 140-143 and 150-153). Detection means (not shown) is used to sense the change in voltage and provide an indication of the sensed velocity.

Abstract: A processing circuit for a magnetoresistive rotary speed sensor (13) or the like having a comparator (11) with switching hysteresis for converting an analog sensor signal into a digital switching signal. An apparatus is provided at the input side of the comparator in order to alternately supply each of the comparator inputs, as a function of the switching signal at the output side of the comparator, symmetrically with a given hysteresis signal as a switching threshold. This apparatus also includes a preamplifier (15) which precedes the comparator non-inverting input and which amplifies the sensor signal, and an offset amplifier (18) of the same construction which precedes the comparator inverting input and which amplifiers an offset signal of a preceding offset network (21). The processing circuit provides a simple, integrable circuit which suppresses offsets and compensates for temperature and supply voltage fluctuations and any spread in tolerances of the circuit components.

Abstract: An rpm sensor, in which an electrically conductive connection between a coil and two electrical lines, leading to the outside via current rails, can be made in a single welding operation each. The rpm sensor is intended for use in anti-lock vehicle brake systems.

Abstract: A system for sensing the position of a rotating steel shaft (1), the system comprising an eddy current sensor and a track (3) fixed to the shaft and going past the sensor, the track being constituted by a strip (4) of electrical insulation material having areas of non-ferromagnetic material with good electrical conductivity regularly distributed around the shaft, wherein the face of the strip (4) provided with the areas of non-ferromagnetic material is glued to the shaft (1). This very simple system serves to obtain a signal of larger amplitude.

Abstract: An antifriction bearing assembly comprises a stationary outer race and a rotatable inner race with two annular rows of rolling elements between the races. A sensor assembly is mounted in the outer race so as to position a sensor between the races and the two rows of rolling elements, and an encoder is mounted on the inner race between the rows of rolling elements. Several sensor assembly and encoder configurations are included.

Abstract: A bearing apparatus is capable of detecting rotational speed of a driven shaft of an automobile. The bearing apparatus has a rotational speed detector and a detected member. The detected member is fixed to an inside member rotating with the driven shaft. The detected member has a hollow cylindrical portion which extends in an axial direction and is provided with a plurality of projections at even intervals in a circumferential direction on its inner peripheral surface. The rotational speed detector is fixed to a cover for covering the rotational speed detector and the detected member. A detector portion of the rotational speed detector is positioned within the hollow cylindrical portion so as to oppose the projections.This is a divisional application of application Ser. No. 07/626,311, filed on Dec. 13, 1990, now abandoned which is a continuation application of now abandoned application Ser. No. 07/469,183, filed on Jan. 24, 1990.

Abstract: A speed sensor tone wheel has a plurality of serrations formed on an inner periphery for engagement with an axially extending annular surface formed on a wheel bearing seal support. The tone wheel is mounted on the support and an outwardly facing surface of the serrations is coined to force the inner ends of the serrations into contact with the annular surface to prevent relative rotation between the tone wheel and the support. Tabs can be formed in the outer periphery of a radially outwardly extending flange of the wheel bearing seal support for extending through open spaces between the serrations and engaging a surface of the tone wheel to trap the tone wheel between the support flange and the tab. Alternatively, an indentation can be formed in the flange to project into an associated one of the serrations.

Abstract: A tachometer system for an internal combustion engine. The tachometer system uses one of two electromagnetic pulse sensing means to detect an electromagnetic signal produced by a firing of the engine. The sensing device may be an antenna or an inductive pickup. One of the signals is chosen and processed. A parameter indicative of pulse timing in the output signal is determined. This parameter is most advantageously a time between different ones of the output signals. The parameter is then converted into a value indicative of revolutions per unit time of the engine. The converting structure is advantageously formed by a personal computer.

Abstract: A pulse rotor is externally supported and secured on a cylindrical face section formed on a hub. The amount by which this pulse rotor projects from an outer ring member is regulated when the pulse rotor is fitted onto the cylindrical face section for supporting. A sensor is provided on the inside of a cover which covers the open end section of the outer ring member. The axial positional relationship between the cover and the outer ring member is uniformly maintained by means of an engaging projection formed on the radially outer peripheral surface of the cover. The distance between the axial end surface of the sensor and the axial end surface of the outer ring member is controlled to a specified value by this means. As a result, the distance between the pulse rotor and the sensor is precisely controlled.

Abstract: Magnetic poles are provided continuously with a pitch .lambda. on the peripheral portion of a drum rotated in accordance with a movement of a moving body. A magnetic sensor is provided in opposition to these poles. The sensor is formed of two magnetoresistive element pairs which are spaced from each other at .lambda./6, and the two elements in each pair are arranged in positions spaced from each other at .lambda./2. The two elements in each pair are connected in series to form a bridge circuit. The signals obtained from the nodes of the series-connected elements in the two element pairs are differentially amplified so that third harmonic wave components are eliminated, and a signal having no distortion and representative of the position or speed of the moving body can be obtained.