JP3292111B2 - Rotation angle detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device suitable for detecting a crank angle or a cam angle of an internal combustion engine.

[0002]

Although [Related Art] This type of rotation angle detection device disclosed in Japanese Patent Kokoku 2-52966 for example, the known detection device is configured of a rotary member as the detection object is complex thereof such as There is a problem. Therefore, the object to be detected with a simple configuration
Using the object to be detected, that is, the rotation angle of the rotating member
A rotation angle detection device capable of detecting a position is desired. For example, a rotation angle detection device as an example is realized by a vane provided on a detection target that rotates integrally with a rotating member, and a detection element that magnetically detects the presence or absence of the vane.
You.

[0003]

THE INVENTION Problems to be Solved However, the above-mentioned
In the case of the rotation angle detection device, the assembly accuracy is low,
The distance between the vane and the detecting element deviates from the set distance.
If this occurs, the detection signal from the detection element is
Judgment of presence of vane because output level fluctuates
In doing so, it is difficult to set a threshold for the detection signal.
You.

On the other hand, as in the detection device of the above-mentioned publication,
Two detecting elements are arranged in the circumferential direction of the body and these detecting elements
Vane based on the change in the output level of the detection signal from the
As for detecting the presence or absence of even near the stop rotation of the detection object
What is either two detection element is opposite both the vane, or liable to be disengaged both from the vane. In the this situation, the detection signals from the two detecting elements
Since those output levels do not change , the rotation angle of the object to be detected, that is, the rotation member with respect to the detection element, can not be detected .

Therefore, when the above-described two-element rotation angle detecting device is used for detecting the crank angle or cam angle of the internal combustion engine, immediately after the start of the internal combustion engine, the fuel injection timing and the ignition timing are determined. Cannot be set correctly. The present invention has been made based on the above-described circumstances, and an object thereof is to provide a rotation angle detection device capable of detecting the rotation angle of a rotating member with a simple configuration even when the rotation is stopped. It is in.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotation angle detecting device according to the present invention, wherein the sensor is a cylindrical member which rotates integrally with a rotating member.
And the rotation angle of the detected object in which
And a sensor for detecting the rotation of the object to be detected.
Passing position where both vane and notch pass through
Is installed to face the vane and detects the notch
Output a first detection signal having a high or low output level.
1 facing the detecting element and a position other than the passing position of the notch
Among the high and low output levels of the first detection signal.
Output the second detection signal with one of the output levels different
And a second detection element,
Are placed apart from each other in the direction of the axis of rotation of the object to be detected.
Have been.

[0007] The first and second detection elements are each a hole.
From elements that detect magnetic flux density, such as elements and magnetoresistive elements
Comprising (Claim 2). Specifically , the second detection element is arranged to detect the leading edge of the vane of the object to be detected. In this case, the vanes of the object to be detected by the first and second detection elements and
When the cutout portion is detected, the higher output level of the second detection signal from the second detection element is lower than the higher output level of the first detection signal from the first detection element.

[0008] When the detection of the vane tip by the second detecting element constrained by interference or the like, the second detection element is to be
The detector may be arranged to detect the base of the vane and the bottom edge of the notch . In this case, when both the first and second detecting element that directly faces the vane body to be detected, these first and second
The output level of the high first and second detection signals from the detector elements side are the same, the first and second detection element base
Even when not over down and confronting the second detection element of cutout portions
Since the bottom edge is detected, the second detection from the second detection element
The output level on the lower side of the signal is the first detection level from the first detection element.
It is higher than the output level on the lower side of the output signal .

[0009]

Referring to FIG. 1, a camshaft 2 is rotatably supported on a cylinder head 4 of an internal combustion engine, and a rotation angle detecting device 6 is disposed at one end of the camshaft 2. I have. The rotation angle detecting device 6 includes a bottomed tubular member 8 that rotates integrally with the camshaft 2, and the tubular member 8 is connected to one end of the camshaft 2 via a bolt 10 with its open end facing outward. And it is mounted coaxially. Therefore, the cylindrical member 8 rotates integrally with the camshaft 2.

The cylindrical member 8 is made of, for example, a magnetic material. The outer peripheral wall of the cylindrical member 8 projects from the peripheral edge 14 of the ring portion 12 by the same length, as is apparent from FIG.
And vanes 16 and 18. Ring part 12
Are located on the camshaft 2 side, and the vanes 16 and 18 are separated from each other in the circumferential direction of the ring portion 12 and extend in the axial direction of the cylindrical member 8. And the circumferential direction of the camshaft 2
The width of the vane 16, 18 along the is constant in the axial direction of the camshaft 2, these widths are different from each other.

The rotation angle detecting device 6 includes a vane 1 of the cylindrical member 8.
A magnetic sensor 20 for magnetically detecting 6, 18 is provided, and this magnetic sensor 20 is fixed to the cylinder head 4 as is clear from FIG. With the rotation of the camshaft 2, the vanes 16 and 18 periodically pass the position immediately before the sensor end face 22 of the magnetic sensor 20,
A small gap (for example, about 0.7 mm) is secured between the sensor end face 22 and the vanes 16 and 18. The magnetic sensor 20 has first and second detecting elements 24 and 26 exposed on the sensor end face 22. The first and second detecting elements 24 and 26 have a Hall element or a magnetoresistive element. Do etc. can be used an element that detect the magnetic flux density of.

As is apparent from FIG. 2, at the sensor end face 22, the first and second detection elements 24 and 26 are separated from each other in the axial direction of the tubular member 8, that is, in the length direction of the vanes 16 and 18. . More specifically, the first detection element 24 is a vane 1
The second detecting element 26 is positioned to detect the front edge of the vanes 16, 18, while the second detecting element 26 is positioned to detect a portion between the front edge and the base of the vanes 16, 18. That is, the second detection element 26 is positioned outside the leading edges of the vanes 16 and 18 when viewed in the axial direction of the tubular member 8.

[0013] As shown in FIG.
Has a built-in permanent magnet 30, and the permanent magnet 30 is disposed near the first and second detection elements 24 and 26. In the case of this embodiment, the first and second detection elements 24 and 26 are magnetoresistive elements mounted on the surface of the permanent magnet 30, and the permanent magnet 30 has a magnetic field, that is, the first and second detection elements 24 and 26. , 26 are generated.

[0014] In the casing 28, first and second detection elements 24 and 26 are electrically connected to the inspection Demawa path substrate 32, connector terminals the detection circuit board 32 through the relay terminal 34 36 Is electrically connected to Now, as the camshaft 2 rotates, the vanes 16, 18
Periodically passes through the sensor end face 22 of the magnetic sensor 20, the magnetic flux density passing through the first and second detecting elements 24 and 26 changes, and as shown in FIG. 24, 26 are the first and second magnetic flux density changes.
Output as detection signals S ₁ and S ₂ .

Here, the first detecting element 24 includes vanes 16,
Since the vanes 16 and 18 are positioned to substantially detect the vanes 16 and 18, the magnetic flux density passing through the first sensing element 24 is greatly increased by the presence of the vanes 16 and 18 when the vanes 16 and 18 pass immediately before. the output level of the first detection signals S ₁ varies greatly. In contrast, the second
Since the detecting element 26 detects the leading edges of the vanes 16 and 18, even if the vanes 16 and 18 pass the position immediately before that, the magnetic flux density penetrating the second detecting element 26 does not increase so much, and the second detection signal output level change of S ₂ is smaller than the output level change of the first detection signal S _1.

In FIG. 4, the 0 level of the first and second detection signals S ₁ and S ₂ is set to the first and second detection elements 24 and 2 respectively.
6, there is no vane 16, 18 in other words, that is, the first and second detection elements 24, 26
8 shows an output level when a space between 8 is detected. The first and second detection signals S ₁ and S ₂ are supplied to the detection circuit board 32.
, And calculates the difference between the first detection signal S ₁ and the second detection signal S ₂ , that is, the detection signal difference ΔS. The output level of the detection signal difference ΔS changes periodically according to the presence or absence of the vanes 16 and 18 as in the case of the first and second detection signals S ₁ and S ₂ .

Thereafter, the detection signal difference ΔS is
2 and is compared with a threshold value T indicated by a dashed line in FIG. 4 and the detection signal difference ΔS, and the level of the detection signal difference ΔS is equal to or larger than the threshold value T. At this time, the comparator outputs the L-level sensor signal S _O to the connector terminal 36. On the other hand, the detection signal difference ΔS
Is lower than the threshold value T, the comparing section outputs the H-level sensor signal _So to the connector terminal 36.

Here, the L-level sensor signal is the vane 1
6 or 18 appears when passing through the sensor end face 22 of the magnetic sensor 20, and the H-level sensor signal S _O
Appears when the space between 6 and 18 passes through the sensor end face 22 of the magnetic sensor 20. According to the rotation angle detection device 6 described above, the rotation of the camshaft 2, that is, the vanes 16, 1
Even when the rotation of the motor 8 is stopped, the sensor signal S _O of the magnetic sensor 20 indicates either the L level or the H level. Therefore, based on the level of the sensor signal S _O , it is possible to detect whether or not the vanes 16, 18 exist immediately before the magnetic sensor 20, that is, the rotation angle range of the cam on the cam shaft 2. this is,
A simple configuration in which the arrangement of the first and second detection elements 24 and 26 of the magnetic sensor 20 is set as described above can be obtained.

As described above, when the rotation angle detecting device 6 is used not only for detecting the cam angle but also for detecting the crank angle in the internal combustion engine, the crank angle and the cam angle can be detected even immediately after the start of the internal combustion engine. The detection becomes possible, and the fuel injection timing and the ignition timing can be appropriately set immediately after the start, and the starting characteristics of the internal combustion engine can be improved. The present invention is not limited to the above-described embodiment. For example, in the case of the rotation angle detecting device 6 of FIG.
0 of the second detecting element 26 is the ring portion 12 of the cylindrical member 8.
And the bases of the vanes 16, 18 are located. In other words, as is clear from FIG. 5, the magnetic sensor 20 moves toward the ring portion 12 as compared with the case of FIG. 2, and is arranged to be rotated by 180 ° about its axis.

The rotation angle detector 6 shown in FIG.
Detection signal S associated with the rotation of the₁Output level
The change is the same as in one embodiment, but
From the second detection signal S_TwoThe output level change of
It is different from the case. That is, in this case, the second detection element 26
1 The vanes 16 and 18 are detected in the same manner as the detection element 24.
The space between vanes 16 and 18 passes just before that
Sometimes, the periphery of the ring portion 12 is detected.
The second detection signal S_TwoNever goes to the 0 level.
As a result, even in the case of the rotation angle detection device 6 of FIG.
The detection signal difference ΔS changes depending on the presence or absence of the vanes 16 and 18.
And the sensor signal S from the magnetic sensor 20 _OIs the binarized signal
Issue.

In the above embodiment and the modified example, the vane 1
Although the vanes 16 and 18 extend in the axial direction of the tubular member 8, the vanes 16 and 18 may extend in the radial direction of the tubular member 8. Can be freely changed. Also, the first
Instead of obtaining the difference between the first and second detection signals, the ratio between the first and second detection signals may be obtained, and the rotation angle range of the rotating member may be detected from a change in this ratio.

[0022]

As described above, according to the rotation angle detecting device of the first and second aspects, even when the rotation of the rotating member , that is, the rotation of the detected object is stopped , the vane and the notch of the detected object are stopped.
The first and second detection elements for the material are the rotation axes of the object to be detected.
Are spaced apart from each other in the
Based on the first and second detection signals from the second detecting element, that Do and capable of detecting the rotation angle of the rotary member by a simple structure.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement of a rotation angle detection device according to one embodiment.

FIG. 2 is a perspective view schematically showing the rotation angle detection device of FIG.

FIG. 3 is a longitudinal sectional view of the magnetic sensor of FIG. 2;

FIG. 4 is a graph showing first and second detection signals, a difference between detection signals, and a change in sensor output in the case of one embodiment.

FIG. 5 is a perspective view schematically showing a rotation angle detection device according to a modification.

FIG. 6 is a graph showing first and second detection signals, a detection signal difference, and a change in sensor output in the case of a modification.

[Explanation of symbols]

 Reference Signs List 8 cylindrical member 16, 18 vane (detected body) 20 magnetic sensor 24 first detection element 26 second detection element

Claims (2)

(57) [Claims] 1. A tubular member that rotates integrally with a rotating member whose rotation angle is to be detected , and includes a vane and a notch portion in a rotating direction.
The object to be detected is formed alternately, and the vane and the cut-out portion are associated with the rotation of the object to be detected.
Are disposed opposite to the passage position through which
Has a high or low output level according to the detection of
A first detection element that outputs the first detection signal, and a first detection element that is opposed to a position other than the passing position of the notch.
Out of the high and low output levels of the first detection signal.
Outputting a second detection signal having one of different output levels
A second detection element, wherein the first and second detection elements are arranged such that a rotation axis of the object to be detected is provided.
A rotation angle detecting device, which is disposed apart from each other in a direction . Wherein each of the first and second detecting elements E
Element that detects magnetic flux density, such as a magnetic element or a magnetic resistance element
Rotation angle detecting apparatus according to claim 1, characterized in that it consists of.