Displacement detecting device
First Claim
1. Displacement detecting device for detecting displacement of a movable intake/exhaust valve;
- comprising;
a spring seat for supporting a spring, a transfer shaft for connecting the spring seat and the intake/exhaust valve, a magnet provided on the spring seat and the magnet magnetized in the direction of movement of the intake/exhaust valve, a magnetic sensor having at least a first surface and a second surface provided between the magnet and the spring, the magnetic sensor detecting magnetic flux generated by the magnet and outputting a sensor output indicative of displacement of the intake/exhaust valve, wherein at least a portion of the first surface of the magnetic sensor lies tangentially to a portion of the magnet, and a piece of a magnetic material provided adjacent to and behind the magnetic sensor, said piece facing the second surface of the magnetic sensor for attracting magnetic flux from the magnet toward the magnetic sensor.
1 Assignment
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Accused Products
Abstract
Displacement of a mechanical element is accurately detected by a simple and inexpensive structure. To provide displacement detecting device including: a mechanical element capable of being displaced; a magnet connected to the mechanical element and magnetized in displacement direction of the mechanical element; and a magnetic sensor for detecting a magnetic flux generated by the magnet and outputting a sensor output corresponding to a detected magnetic-flux value, so as to detect displacement of the mechanical element in accordance with the sensor output. In one embodiment, a Hall element is used as the magnetic sensor and the magnet longer than distance of movement of the mechanical element is used. Thus, an output having a linear relation with displacement of the mechanical element is obtained, and detection of the displacement is easily implemented. The displacement detecting device can be applied to an actuator of intake/exhaust valves of an engine. In another embodiment, a magnetic material provided between the Hall element and a spring to reduce the disturbance caused by the spring. Moreover, a transfer shaft connected to the intake/exhaust valve is made of a non-magnetic material or a material having characteristics close to the non-magnetic material to reduce the effect of leakage flux.
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Citations
21 Claims
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1. Displacement detecting device for detecting displacement of a movable intake/exhaust valve;
- comprising;
a spring seat for supporting a spring, a transfer shaft for connecting the spring seat and the intake/exhaust valve, a magnet provided on the spring seat and the magnet magnetized in the direction of movement of the intake/exhaust valve, a magnetic sensor having at least a first surface and a second surface provided between the magnet and the spring, the magnetic sensor detecting magnetic flux generated by the magnet and outputting a sensor output indicative of displacement of the intake/exhaust valve, wherein at least a portion of the first surface of the magnetic sensor lies tangentially to a portion of the magnet, and a piece of a magnetic material provided adjacent to and behind the magnetic sensor, said piece facing the second surface of the magnetic sensor for attracting magnetic flux from the magnet toward the magnetic sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- comprising;
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10. A displacement detecting device for detecting displacement of an intake/exhaust valve of an internal combustion engine driven by an electromechanical actuator, the displacement detecting device comprising:
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a cylindrical magnet external to the actuator, a portion of the cylindrical magnet substantially enveloping a portion of a transfer shaft of the intake/exhaust valve that extends beyond the actuator so as substantially avoid magnetic flux interference from the actuator, the cylindrical magnet being polarized in the direction of movement of the intake/exhaust valve; and
a magnetic sensor external to the actuator for detecting magnetic flux generated by the cylindrical magnet and outputting a sensor output detecting the displacement of the intake/exhaust valve, the sensor output being substantially linear and substantially free of magnetic flux interference from the electromechanical actuator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
wherein the magnet is provided on the spring. -
16. The displacement detecting device according to claim 15, wherein the magnetic sensor is provided between the magnet and the spring.
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17. The displacement detecting device according to claim 10, wherein the transfer shaft is made of a non-magnetic member or a material having characteristics close to the non-magnetic material.
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18. The displacement detecting device according to claim 15, wherein the spring seat is made of a non-magnetic member or a material having characteristics close to the non-magnetic material.
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19. The displacement detecting device according to claim 10, wherein the magnet is a cylindrical permanent magnet.
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20. The displacement detecting device according to claim 15, wherein the magnet has an annular bore extending in the polarized direction,
wherein a protrusion portion of the spring seat is inserted into the annular bore, wherein one end of the magnet is fixed on the spring seat and the other end of the magnet is fixed with a magnet stopper. -
21. The displacement detecting device according to claim 10, wherein the magnet is fixed to the portion of the transfer shaft by a magnet stopper wherein the magnet stopper in C-shaped.
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Specification