JPH06221807A - Noncontact throttle opening sensor - Google Patents

Abstract

PURPOSE:To reduce an error in detection due to the positional relationship between elements by a method wherein a projection so formed as to have a conical fore end is provided at the center of a rotor magnet and a recession to be fitted to the cone of the fore end of the projection of the rotor magnet is provided in the center of a magnetoresistance element. CONSTITUTION:A rotor magnet 12 is fitted to a shaft 11 rotating in linkage with a throttle valve. A preamplifier of a noncontact throttle opening sensor 10 is built in at a position in proximity to the upper side of the magnet 12 and a hybrid IC board 13 is fixed to a case body 14 to be supported thereby. On the board 13, a magnetoresistance element 15 is provided so that the center thereof is aligned with the center of the shaft 11, and a bias magnet 16 is provided thereon. A projection so formed as to have a conical fore end is provided at the center of the magnet 12, while a recession so formed as to be fitted to the cone is provided in the opposite surface of the board 13. By inserting the case body 14 into a sleeve 19 until the projection is fitted in the recession, it is made possible to assemble the element 15 and the magnet 12 in a state of parallelism being maintained and to determine the relative positions thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve opening sensor for an automobile, and more particularly to a non-contact throttle opening sensor capable of detecting the opening in a non-contact manner.

[0002]

2. Description of the Related Art In recent years, the opening of a throttle valve for controlling the amount of air supplied to an automobile engine is often driven by a motor via an electronic control unit. In this case, the throttle valve opening is detected by the throttle opening sensor and fed back to the electronic control unit.

Since the throttle valve driven by this electronic control device operates more frequently than the conventional throttle valve mechanically linked to the accelerator pedal, it is inevitably durable to the throttle opening sensor. Sex will be required. Therefore, as a throttle opening sensor with improved durability, a sensor that detects the opening in a non-contact manner has been proposed. One of them is to detect the rotation angle of a permanent magnet that rotates by linking with a throttle valve by a magnetoresistive element. A non-contact throttle opening sensor has been proposed.

[0004]

However, in the non-contact throttle opening sensor of the above type, when the rotating magnetic field is detected only by the magnetoresistive element, the resistance change of the magnetoresistive element becomes sinusoidal. Therefore, it is necessary to install a bias magnet so as to overlap the magnetoresistive element and to ensure the linearity of the detection characteristic by forming a bridge with the magnetoresistive element.

FIG. 6 is a diagram showing an example of the detection characteristics of the above-mentioned non-contact throttle opening sensor, in which the horizontal axis represents the rotation angle of the rotor magnet and the vertical axis represents the bridge voltage. That is, if there is no bias magnet, the bridge voltage becomes a sine wave as shown by the broken line, but by installing a bias magnet the peak voltage generation angle is biased in the 0 ° or 180 ° direction and the characteristics of the central part are linear. It is possible to make a shape.

The bridge voltage is 0V at a rotation angle of 90 °.
To achieve this, it is necessary to adjust the balance of the bridge formed by the magnetoresistive element. Therefore, not only an error in the positional relationship among the permanent magnet, the bias magnet, and the magnetoresistive element appears as a detection error, but also it is difficult to adjust the detection characteristics.

The present invention has been made in view of the above problems, and a non-contact throttle opening sensor capable of reducing a detection error due to a positional relationship between elements and an easy adjustment of a detection characteristic. An object is to provide a non-contact throttle opening sensor.

[0008]

A non-contact throttle opening sensor according to a first aspect of the present invention detects a rotor magnet that rotates by linking with a throttle valve and a change in magnetic field due to rotation of the rotor magnet as a change in resistance value. The magnetoresistive element that is arranged close to the rotor magnet and has its center aligned, the bias magnet that is stacked on the magnetoresistive element and that generates a bias magnetic field in the fixed direction, and the tip of the rotor magnet has a conical shape It has a molded protrusion and a concave portion that fits into the cone of the tip of the protrusion at the center of the magnetoresistive element.

A non-contact throttle opening sensor according to a second aspect of the present invention is close to a rotor magnet that rotates by linking with a throttle valve and a rotor magnet that detects a change in magnetic field due to rotation of the rotor magnet as a change in resistance value. And a bias magnet for stacking on the magnetoresistive element and generating a bias magnetic field in a fixed direction, the magnetoresistive element having the centers thereof aligned with each other. A non-contact throttle opening sensor in which the magnetoresistive element and the bias magnet are arranged in the center of an N pole and an S pole facing each other, which are formed in a flat circle shape.

A non-contact throttle opening degree sensor according to a third aspect of the present invention is a semi-disc-shaped sensor in which one magnetic pole is magnetized along the circumference and one magnetic pole is magnetized around the center by rotating in association with a throttle valve. The rotor magnet and a magnetoresistive element formed in a concentric shape and arranged in parallel and close to the disk surface of the semi-disk-shaped rotor magnet and with their centers aligned with each other.

[0011]

In the non-contact throttle opening sensor according to the first aspect of the present invention, the concave portion attached to the back surface of the magnetoresistive element and the conical protrusion attached to the rotor magnet are fitted to each other to form the magnetoresistive element. The parallelism between the rotor magnet and the rotor magnet is maintained. In the non-contact throttle opening degree sensor according to the second aspect of the present invention, since the N pole and the S pole of the rotor magnet are opposed to each other and the magnetoresistive element is installed at the center thereof, when the rotor magnet is eccentric. The magnetic flux density acting on the magnetoresistive element does not change.

In the non-contact throttle opening sensor according to the third aspect of the invention, the resistance value of the magnetoresistive element changes in proportion to the overlapping angle between the semicircular rotor magnet and the semicircular magnetoresistive element. .

[0013]

1 is a top view and a sectional view taken along the line XX of a non-contact throttle opening sensor 10 according to the first invention.
Shaft 1 that rotates by linking with a throttle valve (not shown)
A rotor magnet 12 is screwed into the screw 1. Rotor magnet 1
The hybrid IC substrate 13 in which the preamplifier (not shown) of the non-contact throttle opening sensor 10 is installed at a position close to the upper surface of the non-contact throttle opening sensor 10 with respect to the housing 14 of the non-contact throttle opening sensor 10. Fixedly supported.

A magnetoresistive element 15 is provided on the substrate 13 with its center aligned with the center of the shaft 11, and a bias magnet 16 is provided thereon. FIG. 2 is an enlarged view of a portion A of FIG. 1, in which a protrusion 17 having a conical tip is attached to the center of the rotor magnet 12, and a recess that fits with this cone is formed on the opposing surface of the substrate 13. The recessed part 18 in which is formed is attached.

The protrusions 17 and the recesses 18 are made of a material that easily wears. Therefore, first, the substrate 13 is attached to the housing 1.
4 and then insert the shaft 11 to which the rotor magnet 12 and the protrusion 17 are attached into the sleeve portion 19 of the housing 14 until the protrusion 17 and the recess 18 are completely fitted together. It is possible to assemble the rotor magnet 12 while maintaining an accurate parallel state.

By rotating the rotor magnet 12 several times, for example, in the inspection stage, the projections 17 and the recesses 18 are abraded and the rotation of the rotor is not hindered in the actual use condition. FIG. 3 is a front view of the main part of the non-contact throttle opening sensor according to the second aspect of the invention, in which the magnetoresistive element 15 and the bias magnet 16 are installed on the back surface of the substrate 13.

A rotor magnet 12 which rotates together with the rotating shaft 11.
Substantially U-shaped high-permeability materials 121 and 122 are attached to both electrodes. Therefore, the magnetic flux generated by the rotor magnet 12 is formed in the air in a substantially parallel straight line between the high magnetic permeability materials 121 and 122 facing each other in the air. Then, the magnetoresistive element 15 and the bias magnet 16 are installed in this magnetic flux.

FIG. 4 is a top view of a main portion of the non-contact throttle opening sensor according to the second invention, which shows the rotor magnet 1
The rotation center of 2 is the magnetoresistive element 15 and the bias magnet 1.
Even when decentered from the center of 6, the amount of magnetic flux crossing the magnetoresistive element 15 does not change, and an error due to decentering is prevented. It should be noted that by making the substantially U-shaped high magnetic permeability materials 121 and 122 larger toward the facing surfaces, it is possible to cope with a larger eccentricity.

Further, it is obvious that the rotor magnet 12 itself may be formed in a flat circular shape in which the N pole and the S pole face each other. Although the non-contact throttle opening sensor according to the first and second aspects of the present invention can reduce the detection error due to the positional relationship between the rotor magnet 12, the magnetic resistance element 15, and the bias magnet 16, both of them are possible. It is not possible to reduce the number of man-hours when adjusting the detection characteristics of the sensor.

That is, it is necessary to configure the four magnetoresistive elements in a bridge and adjust the balance of the bridge. FIG. 5 is a perspective view of a non-contact throttle opening sensor according to a third aspect of the present invention, which is a non-contact throttle opening sensor capable of ensuring detection linearity without forming a bridge of magnetic resistance elements. Indicates.

The semi-disk shaped rotor magnet 12 attached to the tip of the rotary shaft 11 has an N pole at the center along the circumference of the rotor magnet S.
The poles are magnetized. Therefore, in the very vicinity of the rotor magnet, the magnetic flux is formed in a radial shape as shown by the alternate long and short dash line 123. On the other hand, the magnetoresistive element 15 is also formed in a semicircular plate shape and a concentric circular shape, and is arranged in parallel with and very close to the rotor magnet.

When the rotor magnet 12 rotates and overlaps with the magnetoresistive element 15, the magnetic flux generated by the overlapped portion of the rotor magnet 12 crosses the magnetoresistive element 15 at a substantially right angle and changes the resistance value. Therefore, the angle at which the rotor magnet 12 and the magnetoresistive element 15 overlap is proportional to the amount of change in resistance, and therefore the rotational angle can be detected by extracting the change in resistance of the magnetoresistive element 15 as a change in voltage or current. It will be possible.

That is, in the non-contact throttle opening degree sensor according to the third aspect of the present invention, the overlap angle is set to 0 ° and 18
It is structurally ensured that the resistance of the magnetoresistive element 15 linearly changes between the position of 0 ° and no special adjustment is required, and a bias magnet is not required, which simplifies the structure. It becomes possible.

[0024]

In the non-contact throttle opening degree sensor according to the first aspect of the present invention, the protrusion attached to the rotor magnet and the recess attached to the magnetoresistive element are fitted to each other when the sensor is assembled. It is possible to uniquely determine the relative position of the rotor magnet and the magnetoresistive element.

In the non-contact throttle opening sensor according to the second aspect of the present invention, the rotor magnet is eccentrically centered by placing the magnetoresistive element and the bias magnet in the two poles of the rotor magnet facing each other. Even in such a case, it is possible to suppress the occurrence of a detection error. In the non-contact throttle opening sensor according to the third invention,
Since the resistance value of the magnetoresistive element changes in proportion to the overlapping angle between the disk-shaped rotor magnet and the magnetoresistive element, and since it is not necessary to use a bias magnet, the detection characteristics can be easily adjusted.

[Brief description of drawings]

FIG. 1 is a top view and a cross-sectional view of a non-contact throttle opening sensor according to a first aspect of the invention.

FIG. 2 is an enlarged view of part A of the non-contact throttle opening sensor according to the first invention.

FIG. 3 is a front view of a main part of a non-contact throttle opening sensor according to a second invention.

FIG. 4 is a top view of a main part of the non-contact throttle opening sensor according to the second invention.

FIG. 5 is a perspective view of a main part of a non-contact throttle opening sensor according to a third invention.

FIG. 6 is a detection characteristic diagram of a non-contact throttle opening sensor.

[Explanation of symbols]

 10 ... Non-contact throttle opening sensor 11 ... Rotating shaft 12 ... Rotor magnet 13 ... Substrate 14 ... Housing 15 ... Magnetoresistive element 16 ... Bias magnet 17 ... Protrusion 18 ... Recess 19 ... Sleeve

Claims (3)

[Claims] 1. A rotor magnet that is rotated by linking with a throttle valve, and a magnetic resistor that is arranged close to and centered with a rotor magnet that detects a change in magnetic field due to rotation of the rotor magnet as a change in resistance value. A non-contact throttle opening degree sensor comprising a magnetic element and a bias magnet which is stacked on the magnetoresistive element and generates a bias magnetic field in a fixed direction, the tip of which is shaped like a cone at the center of the rotor magnet. Non-contact throttle opening sensor, which comprises: a protrusion formed on the magnetoresistive element; 2. A rotor magnet that rotates by linking with a throttle valve, and a magnetic resistance that is arranged close to and centered with a rotor magnet that detects a change in magnetic field due to rotation of the rotor magnet as a change in resistance value. A non-contact throttle opening sensor comprising: an element; and a bias magnet that is stacked on the magnetoresistive element to generate a bias magnetic field in a fixed direction, wherein the rotor magnet has north and south poles opposed to each other. A non-contact throttle opening degree sensor which is formed in a flattened circular shape and in which the magnetoresistive element and the bias magnet are arranged at the centers of the N and S poles facing each other. 3. A semi-disk rotor magnet that rotates in association with a throttle valve and has one magnetic pole centered around the other magnetic pole, and a semi-disk rotor magnet. A non-contact throttle opening sensor including a concentric magnetoresistive element which is arranged in parallel with and close to the disk surface of the disk.