JPH0329694Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a crank angle sensor for controlling an internal combustion engine.

BACKGROUND ART In an electronically controlled internal combustion engine, the rotation angle position of a crankshaft is detected by a crank angle sensor, and ignition timing and fuel injection timing are controlled based on this detection signal. Conventional crank angle sensors are configured to be located within a distributor. On the other hand, the applicant had previously applied for the
In No. 145022, we proposed a crank angle sensor placed on the end face of a cam timing pulley. The rotation angle detection portion of this crank angle sensor is formed by a protruding rib extending concentrically at right angles from the end surface of the cam timing pulley. Further later, in order to form such ribs, a structure as shown in FIG. 4 was proposed. In FIG. 4, a signal rotor 101 having equally spaced ribs 100 for angle detection is press-formed, and this rotor 101 is fixed to an end surface of a cam timing pulley 102. The signal rotor 101 is further formed with a semi-cylindrical protruding rib 103 extending over an angular range of 180 degrees for reference position detection, the base of which is cylindrical and is integrated into the signal rotor 101 by welding. It's getting old.

Problems to be solved by the invention In the above-mentioned detection part structure, the outer protruding rib 100
There is a problem in that it is difficult to obtain concentricity between the inner protruding rib 103 and the inner protruding rib 103. Therefore, a relatively large gap is required between the fixed detector 104 arranged relative to the rotation detection section and such a detection section,
Detection accuracy deteriorates. Moreover, if welding is performed, the positional deviation between the two protruding ribs will become even larger, and unless welding is used, the cylindrical rib 103 cannot be properly fixed to the rotor 101, and a more complicated structure is required.

Means for Solving the Problems In order to solve the above problems, the present invention provides a cam timing pulley attached to the end of the camshaft that drives the intake valve or the exhaust valve, and a cam timing pulley that is attached to the end of the camshaft that drives the intake valve or the exhaust valve. a signal rotor consisting of an annular flat disk having a center;
a first detection section formed along the outer circumferential edge of the signal rotor, a second detection section formed along the inner circumference edge of the signal rotor, and a proximal position opposite to the two protrusion sections; a pair of fixedly installed angle detectors, and the signal rotor is attached to the cam timing pulley at a radially intermediate portion between the outer circumferential edge and the inner circumferential edge for crank angle detection. A crank angle sensor is provided.

Function When the internal combustion engine is operated and the timing pulley of the camshaft is driven from the timing pulley attached to the crankshaft via the timing belt, the camshaft rotates at half the speed of the crankshaft and the intake air of the engine is driven. Open and close a valve or exhaust valve.

A signal rotor consisting of an annular flat disc is attached to the timing pulley of the camshaft, so this rotor also rotates integrally with the timing pulley, and the first rotor formed along the outer periphery of the signal rotor
The detection part and the second detection part formed along the inner peripheral edge move relative to a pair of angle detectors, and the displacement angle, that is, the rotation angle of the camshaft or crankshaft is detected as a signal by the angle detector. is converted to and output to the outside.

In the present invention, since the signal rotor is attached to the cam timing pulley at a radially intermediate portion between its outer circumferential edge and inner circumferential edge,
The length from the mounting position to the tips of the outer circumferential edge and the inner circumferential edge is the shortest, and the first and second detecting parts formed along them do not shake significantly due to vibrations, etc. The distance between them and the corresponding angle detectors installed in close proximity is also kept substantially constant.

Embodiment In FIGS. 1 and 2, reference numeral 1 indicates a cylinder head, and reference numeral 2 indicates an end of a camshaft that drives an intake valve or an exhaust valve (not shown). 3 is a seal. It is clear that a cam timing pulley 5 is fixed to the end of the camshaft 2 by a bolt 4, and that the cam timing pulley 5 and the camshaft 2 are on the same axis. The cam timing pulley 5 has a thin disk portion 6 and a thick flange portion 7, teeth are formed on the outer peripheral surface of the flange portion 7, and the cam timing pulley 5 is connected to a crankshaft (not shown) by a timing belt. be able to. The camshaft 2 thus makes one revolution for every two revolutions of the crankshaft.

As shown in FIG. 1, on one end surface of the flange portion 7 of the cam timing pulley 5, a signal rotor 8 consisting of an annular flat disk with a large opening in the center is coaxial with the axis of the camshaft 2. installed. That is, as shown in FIGS. 1 and 2, they are fixed with screws 9. A first detection section is formed on the disc-shaped signal rotor 8 and includes vanes 10 extending radially outward at regular intervals along its outer periphery. It also protrudes outward. Further, along the inner circumferential edge of the signal rotor 8, a second detection section is formed which is made of a blade 11 extending over an angular range of 180 degrees.

The cylinder head 1 includes blades 10 of each detection section,
Angle detectors 15 and 16 each having a U-shaped cross section and which can be sandwiched between 11 and 11 with a small gap are fixed by a common bracket 17 and screw 18. A detailed example of the angle detector 15 is shown in FIG. 3, in which a permanent magnet 20 and a yoke 21 are embedded in one side of the U-shape, and a Hall element 22 and a yoke 23 are embedded in the other side. is buried. As shown in FIG. 3, when the magnetic blade 10 is inside the detector 15, a magnetic circuit as shown by arrow A is formed, and the detection output of the Hall element 22 becomes low, and the blade 10
When 0 is not present in the detector 15, a magnetic circuit shown by arrow C is formed and the detection output of the Hall element becomes high. Therefore, the position of the crankshaft can be known from the output of the Hall element 22, and the blades 10 on the outer peripheral side of the signal rotor 8 are used to detect the crank position at every predetermined angle.
On the other hand, the inner circumferential blade 11 is used, for example, to detect a reference position of the crankshaft every 720 degrees, which indicates that the piston of a particular cylinder is at compression top dead center.

The signal rotor 8 is obtained by press-molding a single flat plate, and the obtained shape is also planar. Therefore, since the thickness is constant, the air gap between the angle detectors 15 and 16 is also uniform, and the air gap can be set small. This means improved detection accuracy. Furthermore, when assembling, it is sufficient to simply fasten with screws, and the possibility of distortion occurring is extremely small. It is clear that the number of parts can be reduced and the manufacturing cost can be reduced.

Next, to explain the assembly order, cylinder head 1
Attach the camshaft 2 and angle detectors 15 and 16 to. At this time, the bracket 17 to which the angle detectors 15 and 16 are attached is attached to a dowel pin (not shown).
etc., it can be installed in an accurate position. The signal rotor 8 is the cam timing pulley 5
This cam timing pulley 5 is assembled to the camshaft 2 in advance. At this time, there are portions on the inner and outer peripheral edges of the signal rotor 8 where the blades 10 and 11 do not protrude, and the cam timing pulley 5 is pushed in by aligning the positions of the blades with the angle detectors 15 and 16.

Effects of the invention As explained above, according to the invention, since the two detection parts are formed by a single signal rotor component, it is possible to eliminate the positional deviation between the two detection parts, and to obtain an inexpensive crank angle sensor. The angle detection accuracy can also be improved. In particular, the signal rotor of the present invention is attached to the cam timing pulley at the radially intermediate portion between its outer and inner edges, so it does not wobble or deform due to vibrations, and the outer and inner edges are connected to each other. The two detection parts formed along the inner peripheral edge also
Since the distance to the other party's angle detector does not change, the distance between them can be made very small, improving the accuracy of the detector and providing excellent responsiveness and reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the crank angle sensor according to the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1,
FIG. 3 is a diagram showing a detailed example of an angle detector, and FIG. 4 is a diagram explaining a conventional structure. 2...Camshaft, 5...Cam timing pulley, 8...Signal rotor, 10, 11...Blade, 15, 16...Angle detector.

Claims (1)

[Scope of utility model registration request] a cam timing pulley attached to the end of a camshaft that drives an intake valve or an exhaust valve;
a signal rotor consisting of an annular flat disk having the same center as the axis of the camshaft; and a first signal rotor formed along the outer periphery of the signal rotor.
a second detection section formed along the inner circumferential edge of the signal rotor, and a pair of angle detectors fixedly installed at proximate positions opposite to the two detection sections, A crank angle sensor, wherein the signal rotor is attached to the cam timing pulley at a radially intermediate portion between the outer peripheral edge and the inner peripheral edge for crank angle detection.