摘要:
A linear positional displacement detector including a magnetic sensor unit (23) having a magnetic sensing surface formed by a ferromagnetic magnetoresistance element (23a) having a predetermined pattern, and an elongated permanent magnet (22) having a magnetic pole face (22a) at each end. The permanent magnet (22) is movable along its longitudinal axis and magnetically coupled with the magnetic sensor unit (23) with the longitudinal axis positioned on an extended surface of the magnetic sensing surface (23b). A positional displacement of the permanent magnet (22) along the longitudinal axis is detected as a change in the direction of a magnetic flux crossing in parallel the magnetic sensing surface (23b).
摘要:
A magnetic detector capable of being easily assembled and diminishing fluctuation in magnetic detection accuracy includes: magnetic resistance elements whose resistance value changes according to change in magnetic field generated by rotation of a multi-polarized rotor; an IC formed by integrating a signal processing circuit section that outputs a signal corresponding to multi-polarization of the rotor based on change in resistance values of the magnetic resistance elements; a lead frame mounted with the IC and connected to an external output terminal for externally outputting an output signal from the signal processing circuit section; a magnet applying a bias magnetic field to the magnetic resistance elements; and a magnetic guide for correcting lines of magnetic force from the magnet. The IC, lead frame and magnetic guide are preliminarily assembled to serve as a first assembly, and the magnet and external output terminal are preliminarily assembled to serve as a second assembly.
摘要:
A magnetic detection apparatus can be improved in its product yield. The magnetic detection apparatus includes a resin compact having a the magnet arranged in opposition to an object to be detected for generating a magnetic field, an IC chip with a magnetic detection part built therein for detecting a change in the magnetic field in accordance with movement of the object to be detected, and an IC package in which a lead frame having the IC chip installed thereon is sealed with a resin. A method for manufacturing such a magnetic detection apparatus includes a signal adjustment step for adjusting a signal generated from the magnetic detection part in a state in which the magnetic field is applied to the magnetic detection part to correct a deviation of the signal of the magnetic detection part generated in accordance with a relative displacement between the magnetic detection part and the magnet.
摘要:
A magnetic detection apparatus is able to ensure good performance in detecting the position of an detected portion even with a shift or displacement in the position of a magnetoelectric conversion element. The magnetic detection apparatus includes at least one magnetoelectric conversion element 15 disposed to face one of teeth 12a and grooves 12b of a rotating member 11, a magnet 14 with a direction of magnetization thereof oriented in a direction perpendicular to a radial direction of the rotating member 11 in which the magnet 14 faces the rotating member 11, and a magnetic guide 21 having a first pole projection 21a and a second pole projection 21b formed in a spaced apart relation with respect to each other in a radial direction of the magnetic moving object in which the magnetic guide 21 faces one of the teeth 21a and the grooves 21b of the rotating member 11. The at least one magnetoelectric conversion element is disposed between the first and second pole projections when viewed from a direction perpendicular to the radial direction of the magnetic moving object in which the magnetic guide faces one of the teeth 21a and the grooves 21b of the rotating member 11.
摘要:
A magnetic detector is disclosed with a power-on function which can essentially eliminate temperature characteristics of a magnetic field sensing device and improve edge detecting accuracy of alternately projected and recessed portions of a moving member of magnetic material. The magnetic detector comprises a magnet for generating a magnetic field, a rotary member of magnetic material disposed with a predetermined gap remaining relative to the magnet and having alternately projected and recessed portions to change the magnetic field generated by the magnet, a magnetoresistive device comprising a plurality of magnetic field sensing elements and detecting changes in the magnetic field by movement of the rotary member of magnetic material, and a magnetic guide for adjusting changes in the magnetic field caused by the alternately projected and recessed portions of the rotary member of magnetic material.
摘要:
A magnetic detector is disclosed with a power-on function which can essentially eliminate temperature characteristics of a magnetic field sensing device and improve edge detecting accuracy of alternately projected and recessed portions of a moving member of magnetic material. The magnetic detector comprises a magnet for generating a magnetic field, a rotary member of magnetic material disposed with a predetermined gap remaining relative to the magnet and having alternately projected and recessed portions to change the magnetic field generated by the magnet, and a magnetoresistive device comprising a plurality of magnetic field sensing elements and detecting changes in the magnetic field by movement of the rotary member of magnetic material. The magnetic flux crosses the plurality of magnetic field sensing elements at a first predetermined angle when the recessed portion of the moving member of magnetic material is opposed to the magnetic field sensing device, and the magnetic flux crosses the plurality of magnetic field sensing elements at a second predetermined angle when the projected portion of the moving member of magnetic material is opposed to the magnetic field sensing device. The first and second predetermined angles are symmetrical with respect to a direction vertical to a plane in which the plurality of magnetic field sensing elements are arranged.
摘要:
The invention provides a sensing device capable of outputting a correct signal precisely corresponding to a particular position (angle) of, for example a protruding or recessed portion of a rotating member made of a magnetic material. The sensing device includes: a magnet for generating magnetic field; a rotary member of magnetic material for changing a magnetic field generated by the magnet, the rotary member of magnetic material being disposed a predetermined distance apart from the magnet; and a giant magnetoresistance device for detecting the varying magnetic field, the operating range of the giant magnetoresistance device being set such that the change in resistance of the giant magnetoresistance device is uniform over the entire operating range in both directions of change in the magnetic field induced by the rotary member of magnetic material, wherein the giant magnetoresistance device is disposed in such a manner that the center of the magnetic field sensing plane of the giant magnetoresistance device deviates from the center of the magnet in a direction parallel to a plane containing the displacement direction of the rotary member of magnetic material.
摘要:
A magnetic detection apparatus includes a first comparison circuit that waveform-shapes the amplitude of a detection signal from magneto-electric transducers by DC coupling, a third comparison circuit that waveform-shapes the detection signal by AC coupling, an oscillation circuit having a natural frequency, a control circuit that counts the output of the first comparison circuit by using the oscillation means, and a selection circuit that selects the output of the first comparison means and the output of the second comparison means. The control circuit counts rising from the next rising or falling from the next falling of an output rectangular wave of the first comparison circuit, and provides output to the selection circuit at the time point at which the count value reaches a desired value. The selection circuit selects and outputs the output rectangular wave of the first comparison circuit or the third comparison circuit.
摘要:
The magnetic sensor in the invention is arranged to detect a change of magnetic field caused by a movement of the magnetic movable by a magnetic sensor element arranged with a gap to the magnetic movable, to convert the detected change of magnetic field by first and second bridge circuits into electric signals, to generate first and second rectangular-wave signals by first and second comparator circuits depending upon the electric signals, and to form a signal having at least four levels by a signal forming circuit, thereby detecting a moving direction of the magnetic movable depending upon a level-change order in the signal. This makes it possible to detect a rotating direction of the magnetic movable rapidly and correctly.
摘要:
A magnetic detection device is provided in which a first signal is outputted in accordance with the mutual phase relationship between the output of a first magnetoelectric conversion output circuit and the output of a second magnetoelectric conversion output circuit that are based on the movement, in forward direction, of a detection subject, thereby generating a pulse of a high level 1 and a low level 1; a second signal is outputted in accordance with the mutual phase relationship between the output of the first magnetoelectric conversion output circuit and the output of the second magnetoelectric conversion output circuit that are based on the movement, in forward direction, of the detection subject; an output signal processing circuit for generating a pulse of a high level 2 and a low level 2 is provided; and not only the pulse of the high level 1 and the low level 1 does not cross the other comparison level, but also the pulse of the high level 2 and the low level 2 does not cross the one comparison level.