Rotational angle detector

Abstract

Conductive wires run parallel to each other and connect a Hall element and an ECU. The conductive wire includes an extracting part and a wiring part. The extracting part runs along a surface of a base, on which the Hall element is positioned, and in a direction of a sensitivity of the Hall element. The wiring part extends from the extracting part and runs near a rotating crankshaft in an axial direction of the crankshaft. Similar to the conductive wire, the conductive wire includes an extracting part and a wiring part. Conductive wires run parallel to each other and connect a Hall element and the ECU. The conductive wires include an extracting part and a wiring part, and an extracting part and a wiring part, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings. In the drawings:

FIG. 1A is a cross-sectional view of a rotational angle detector in FIG. 1B taken along a line IA-IA according to a first embodiment of the present invention;

FIG. 1B is a cross-sectional view of the rotational angle detector in FIG: 1A taken along a line IB-IB according to the first embodiment;

FIG. 2A is a schematic view showing a magnetic field that permanent magnets generate;

FIG. 2B is a schematic view showing the magnetic field that the permanent magnets generate;

FIG. 2C is a schematic view showing the magnetic field that the permanent magnets generate;

FIG. 3A is a diagram illustrating a method of detecting a rotational angle by the rotational angle detector;

FIG. 3B is a diagram illustrating the method of detecting the rotational angle by the rotational angle detector;

FIG. 3C is a diagram illustrating the method of detecting the rotational angle by the rotational angle detector;

FIG. 4 is a table illustrating the method of detecting the rotational angle by the rotational angle detector;

FIG. 5 is a diagram illustrating measures against noise according to the first embodiment;

FIG. 6 is a diagram illustrating the measures against the noise according to the first embodiment;

FIG. 7A is a cross-sectional view of a rotational angle detector in FIG. 7B taken along a line VIIA-VIIA according to a second embodiment of the present invention;

FIG. 7B is a cross-sectional view of the rotational angle detector in FIG. 7A taken along a line VIIB-VIIB according to the second embodiment;

FIG. 8 is a schematic view showing a rotational angle detector according to a first conventional art;

FIG. 9 is a diagram showing a result of a noise test that is performed on the rotational angle detector according to the first conventional art;

FIG. 10 is a schematic view showing a rotational angle detector according to a second conventional art; and

FIG. 11 is a diagram showing a result of a noise test that is performed on the rotational angle detector according to the second conventional art.

Claims

1. A rotational angle detector for detecting rotation of a detection object comprising: a magnetic field generating means for generating a magnetic field;a magnetism detecting element positioned in the magnetic field for outputting an output signal in correspondence with variation in the magnetic field caused by rotation of the detection object;a pair of conductive wires that are connected to the magnetism detecting element for transmitting the output signal; andan electronic means for detecting a rotational angle of the detection object based on the output signal, wherein: the pair of conductive wires includes a corresponding pair of wiring parts, which run in a virtual plane that is generally perpendicular to a direction of a sensitivity of the magnetism detecting element and extend along a rotational axis of the detection object in an area where the magnetic field is varied by the rotation of the detection object.

2. The rotational angle detector according to claim 1, wherein the pair of conductive wires includes a corresponding pair of extracting parts, wherein: the pair of extracting parts runs along a surface of the base, on which the magnetism detecting element is positioned; andthe pair of extracting parts extends to the corresponding pair of wiring parts.

3. The rotational angle detector according to claim 2, wherein each one of the pair of extracting parts runs in a virtual plane that is generally parallel to a direction of the magnetic field.

4. The rotational angle detector according to claim 2, wherein each one of the pair of extracting parts extends in the direction of the sensitivity of the magnetism detecting element.

5. The rotational angle detector according to claim 4, further comprising a pair of terminals that are disposed in the direction of the sensitivity of the magnetism detecting element, wherein the pair of conductive wires is connected to the magnetism detecting element via the corresponding pair of terminals.

6. The rotational angle detector according to claim 1, wherein: the magnetism detecting element is one of a plurality of magnetism detecting elements;the pair of conductive wires is one pair of a plurality of pairs of conductive wires, wherein each one pair of the plurality of pairs of conductive wires is connected to a corresponding one of the plurality of magnetism detecting elements;the pair of wiring parts is one pair of a plurality of pairs of wiring parts;the pair of extracting parts is one pair of a plurality of pairs of extracting parts, wherein each one pair of the plurality of pairs of conductive wires includes a corresponding pair of the plurality of pairs of wiring parts, and a corresponding pair of the plurality of pairs of extracting parts; anda distance between any one pair of the plurality of pairs of wiring parts, which are connected to a corresponding one of the plurality of magnetism detecting elements, is approximately the same.

7. The rotational angle detector according to claim 1, wherein: the magnetic field generating means generates a generally parallel magnetic field near the rotational axis of the detection object;the magnetism detecting element is positioned near the rotational axis of the detection object; andthe pair of conductive wires runs near the rotational axis of the detection object.