Abstract: This magnesium oxide powder contains secondary particles in which a plurality of primary particles of magnesium oxide having a crystal phase and a grain boundary phase are at least partially fused together by the grain boundary phase, and a median diameter obtained by a laser diffraction scattering method is 300 ?m or less.

Abstract: This magnesium oxide powder contains secondary particles in which a plurality of primary particles of magnesium oxide having a crystal phase and a grain boundary phase are at least partially fused together by the grain boundary phase, and a median diameter obtained by a laser diffraction scattering method is 300 µm or less.

Abstract: A limiting portion of a support member, which rotatably supports an accelerator pedal, forms a gap between a contacting portion of the accelerator pedal and the limiting portion in a state where the accelerator pedal is rotated in a depressing direction. A cover member is provided to one of the support member and the accelerator pedal and covers the gap at any rotational position of the accelerator pedal within a rotatable range of the accelerator pedal.

Abstract: A limiting portion of a support member, which rotatably supports an accelerator pedal, forms a gap between a contacting portion of the accelerator pedal and the limiting portion in a state where the accelerator pedal is rotated in a depressing direction. A cover member is provided to one of the support member and the accelerator pedal and covers the gap at any rotational position of the accelerator pedal within a rotatable range of the accelerator pedal.

Abstract: External magnetic members are provided outside the outer periphery of a rotor. When the rotor is positioned around its turning angle of 70 degrees, part of the magnetic fluxes generated by magnets pass through the external magnetic members. This makes it possible to reduce the magnetic fluxes passing through Hall ICs around the turning angle of 70 degrees, thereby linearizing the change characteristic of the magnetic flux density. Thus, it is possible to generally linearize the change characteristic of the density of the magnetic fluxes through the Hall ICs 7, with the detectable angle range kept wide.

Abstract: A rotation angle sensing device for detecting a relative rotation angle between a rotor and a stator includes main magnets, fixed in the rotor, and hole ICs, fixed in the stator. The hole ICs detect magnetic flux of the main magnets , and the relative rotation angle therebetween is detected. A supportive magnet is disposed between the hole ICs so as to offset the magnetic flux of the main magnets. Accordingly, a rotation angle in which the magnetic flux density detected in the hole ICs becomes 0 [mT] can be changed by the supportive magnet. Therefore, a 0° position of the rotation angle can be set to the rotation angle in which the magnetic flux density is detected as 0 [mT], and moreover the detectable range of the rotation angle can be enlarged to be more than 90°.

Abstract: A magnet is provided to one of two members, which make relative rotation therebetween. First and second Hall elements are arranged adjacent to each other and are provided to the other one of the two members. A magnetic sensing surface of the first Hall element is generally perpendicular to a magnetic sensing surface of the second Hall element, and a relative rotational angle between the two members is determined through the first and second Hall elements based on a magnetic flux, which is generated by a magnetic flux generating portion of the magnet and passes through the first and second Hall elements toward a magnetic flux attracting portion of the magnet.

Abstract: A magnet is provided to one of two members, which make relative rotation therebetween. First and second Hall elements are arranged adjacent to each other and are provided to the other one of the two members. A magnetic sensing surface of the first Hall element is generally perpendicular to a magnetic sensing surface of the second Hall element, and a relative rotational angle between the two members is determined through the first and second Hall elements based on a magnetic flux, which is generated by a magnetic flux generating portion of the magnet and passes through the first and second Hall elements toward a magnetic flux attracting portion of the magnet.

Abstract: A method for calibrating a rotation angle sensor having a magnet, a magnetic detector disposed in a magnetic field of the magnet for outputting a detected value indicative of a direction of the magnetic field that varies in accordance with a rotation angle of a rotatable member, and an output circuit which transforms the detected value to an output value in accordance with a transforming characteristic and outputs the output value, the method entailing: assembling the magnet, the magnetic detector and the output circuit to a device that has the rotatable member; rotating the rotatable member to a predetermined reference angle; measuring the detected value or the output value as a measured value when the rotatable member is at the reference angle; and setting the transforming characteristic based on the measured value so that the output circuit outputs a reference output value at the reference angle.

Abstract: External magnetic members are provided outside the outer periphery of a rotor. When the rotor is positioned around its turning angle of 70 degrees, part of the magnetic fluxes generated by magnets pass through the external magnetic members. This makes it possible to reduce the magnetic fluxes passing through Hall ICs around the turning angle of 70 degrees, thereby linearizing the change characteristic of the magnetic flux density. Thus, it is possible to generally linearize the change characteristic of the density of the magnetic fluxes through the Hall ICs 7, with the detectable angle range kept wide.

Abstract: Non-contact type Hall ICs detecting an rotation angle of a throttle valve, a stator core strengthening a magnetic field around the Hall ICs, a lead frame connecting the Hall ICs to an outside ECU are integrated in a sensor cover by resin molding. Thus, the Hall ICs, the stator core, and the lead frame are accurately positioned in the sensor cover. As a result, the Hall ICs are accurately positioned with respect to a permanent magnet disposed in a shaft side of the throttle valve, thereby improving an accuracy of detecting the rotation angle of the throttle valve.

Abstract: Non-contact type Hall ICs detecting an rotation angle of a throttle valve, a stator core strengthening a magnetic field around the Hall ICs, a lead frame connecting the Hall ICs to an outside ECU are integrated in a sensor cover by resin molding. Thus, the Hall ICs, the stator core, and the lead frame are accurately positioned in the sensor cover. As a result, the Hall ICs are accurately positioned with respect to a permanent magnet disposed in a shaft side of the throttle valve, thereby improving an accuracy of detecting the rotation angle of the throttle valve.

Abstract: Non-contact type Hall ICs detecting an rotation angle of a throttle valve, a stator core strengthening a magnetic field around the Hall ICs, a lead frame connecting the Hall ICs to an outside ECU are integrated in a sensor cover by resin molding. Thus, the Hall ICs, the stator core, and the lead frame are accurately positioned in the sensor cover. As a result, the Hall ICs are accurately positioned with respect to a permanent magnet disposed in a shaft side of the throttle valve, thereby improving an accuracy of detecting the rotation angle of the throttle valve.

Abstract: A rotation angle sensing device for detecting a relative rotation angle between a rotor and a stator includes main magnets, fixed in the rotor, and hole ICs, fixed in the stator. The hole ICs detect magnetic flux of the main magnets , and the relative rotation angle therebetween is detected. A supportive magnet is disposed between the hole ICs so as to offset the magnetic flux of the main magnets. Accordingly, a rotation angle in which the magnetic flux density detected in the hole ICs becomes 0[mT] can be changed by the supportive magnet. Therefore, a 0° position of the rotation angle can be set to the rotation angle in which the magnetic flux density is detected as 0[mT], and moreover the detectable range of the rotation angle can be enlarged to be more than 90°.

Abstract: An angular position detecting apparatus using a magnetic detecting element, which can voluntary widely set an output change characteristic of the magnetic detecting element with respect to angular positions. An angular position detecting apparatus includes a cylindrical yoke, and a magnet fixed to a predetermined position in the cylindrical yoke. A magnetic detecting element, which is fixed to a rotor, is provided in a magnetic field generated between the magnet and the cylindrical yoke, so that a position of the magnetic detecting element is shifted from a rotation axis P of the rotor by a predetermined distance r. A ferromagnetic thin film magnetic resistance element applies a magnetic field which has intensity so that outputs from the elements are saturated. As a result, the magnetic detecting element generates outputs depending only on a magnetic flux detection angle &thgr;s independent of an influence of changes of magnetic field intensity due to temperature changes.

Abstract: In an intake air control device, a valve gear for driving a shaft of a throttle valve is made of non-magnetic metal that does not interfere with a magnetic circuit constituted by split type permanent magnet and yoke. Accordingly, as the magnetic flux from the magnetic circuit is effectively used without leakage to the valve gear, an opening degree of the throttle valve is accurately detected by a non-contact type Hall element. Further, it is not necessary to reinforce with other metal a ring shaped fixing portion of the valve gear that is rigidly fixed to an end of the shaft by staking or welding and an outer protrusion of the valve gear that comes in hitting contact with a stopper of a throttle body when the throttle valve is fully closed, resulting in less number of component parts and lower cost.

Abstract: If outputs of a couple of Hall ICs constituting a throttle valve position sensor are within an operating range of throttle valve position, and if a relationship between the outputs are within a predetermined error range, both the Hall ICs are determined to be normal. In contrast, if the outputs are equal to an upper clamp voltage or a lower clamp voltage, and if a relationship between the outputs is out of the predetermined error range, at least one of the Hall ICs is determined to be abnormal. Furthermore, if the outputs are within a failure reference voltage range, it is determined that there is an abnormality between the throttle valve position sensor and an ECU. In this way, abnormalities in the sensor and abnormalities between the sensor and the ECU can also be detected.

Abstract: Hall ICs constituting a redundant throttle valve position sensor are used to measure a rotational angle value indicative of a position of a throttle valve and a temperature value indicative of an ambient temperature change, which is continuously monitored, around the Hall ICs. The rotational angle value measured by the Hall ICs is appropriately adjusted based on the measure temperature value of its own, and a throttle valve position is determined in an externally connected ECU based on the adjusted angle value. In addition, the temperature value measured by one Hall IC is inputted to the ECU. In the ECU, various control values, such as a resistance value of an electric motor, can be appropriately adjusted based on the measured temperature value.

Abstract: The rotational angle of a rotatable object (such as the throttle valve of an automobile engine) is accurately detected by a rotational angle detector having a magnetic sensor placed in a magnetic field, the direction of which varies according to the rotational angle. The magnetic sensor generates an output that varies sinusoidally according to rotational angle. The sinusoidal output is converted into a signal that is proportional to the rotational angle under arc-sine or arc-cosine transformation. The converted signal correctly represents the rotational angle in a wide angle range. The sensor element and the circuit for converting the sensor output into the proportional output signal may be built in a single-chip integrated circuit to simplify detector structure.

Abstract: In an intake air control device, a valve gear for driving a shaft of a throttle valve is made of non-magnetic metal that does not interfere with a magnetic circuit constituted by split type permanent magnet and yoke. Accordingly, as the magnetic flux from the magnetic circuit is effectively used without leakage to the valve gear, an opening degree of the throttle valve is accurately detected by a non-contact type Hall element. Further, it is not necessary to reinforce with other metal a ring shaped fixing portion of the valve gear that is rigidly fixed to an end of the shaft by staking or welding and an outer protrusion of the valve gear that comes in hitting contact with a stopper of a throttle body when the throttle valve is fully closed, resulting in less number of component parts and lower cost.