JPH01119701A - Throttle sensor - Google Patents

Abstract

PURPOSE:To detect the resolving power in a low opening region with high accuracy, by detecting the synthetic magnetic field by the rotary magnetic field of the first magnetic synchronous to the rotation of a throttle valve and that of a throttle valve stem and the bias magnetic field of the second magnet. CONSTITUTION:A throttle valve 2 is fixed to a throttle valve stem 3 and both of them are mounted on a throttle body 1 through a bearing 5 to rotate corresponding to the operation of an accelerator. The first magnet 6 is mounted on the yoke 16 fixed to one end of the stem 3 so that N- and S-poles are opposed to each other to form a magnetic circuit and the rotary magnetic field 7 thereof rotates along with the stem 3. The second magnet 8 and a magnetoelectric converter element 9 are integrally fixed to the base plate 11 fixed in the body 1 in a superposed state. Herein, the magnet 8 is deflected toward a rotary direction with respect to the magnetic field and fixed to the center of the N- and S-poles of the magnet 6. The synthetic magnetic field 17 formed by the magnetic field 7 and the bias magnetic field 18 of the magnet 8 changes corresponding to the deflection of the magnetic field 7 and this change is detected by the element 9. Sine wave output of one cycle is obtained from the element 9 by one rotation of a throttle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a throttle sensor, and particularly to a throttle sensor suitable for non-contact detection of the rotational opening degree of a throttle valve in an internal combustion engine of an automobile.

[Conventional technology]

In the conventional sensor, as described in JP-A-56-107119, the output voltage y from the magnetoelectric transducer is expressed as y=Acos2 with respect to the direction of the magnetic field, that is, the throttle rotation opening.
It began to exhibit the characteristic θ0B. This means that two cycles of sine wave output are obtained when the throttle rotates once (360'').

[Problem that the invention seeks to solve]

In the above conventional technology, as shown in Figure 6, the output from the magnetoelectric transducer is a sine wave with two cycles when the throttle rotates once, so the rotational opening is within the detection range of the throttle sensor. In the range of 0 to 90°, the accuracy (resolution) in the low opening range is insufficient, and if you want to improve the accuracy in the low opening range, the value obtained from the sine wave in the high opening range becomes two, and the high opening range (
It was a stroke of luck that detection of angles (near 90°) became impossible.

The purpose of the present invention is to achieve the following when the throttle rotates once (360
An object of the present invention is to provide a throttle sensor capable of detecting resolution in a low opening range with high accuracy by making it possible to obtain a sine wave output of one period at 10°.

[Means for solving problems]

The above object is achieved by supplying the magnetoelectric transducer with a composite magnetic field formed by a rotating magnetic field generated in synchronization with the rotation of the throttle valve shaft and a bias magnetic field generated by the second magnet.

[Effect]

In the throttle sensor of the present invention, the magnetoelectric conversion element senses a composite magnetic field formed by a rotating magnetic field generated in synchronization with rotation of the throttle valve shaft and a bias magnetic field generated by the second magnet. This causes the throttle to rotate one revolution (36
0@), one period of sine wave output can be obtained from the magnetoelectric transducer, so the throttle opening is 0 to 9.
Accuracy (resolution) in the low opening range in the 0″ range
will improve.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. 3 is an overall sectional view according to the present invention. Reference numeral 1 denotes a throttle body, and a throttle valve 2 is fixed to a throttle valve shaft 3 by a fixing screw 4, and rotates in response to operation of an accelerator pedal (not shown). And throttle valve 2. Throttle valve shaft 3
is attached to the throttle body 1 through a bearing 5.

A yoke 16 is made of a magnetic material and is fixed to one end of the throttle valve shaft 3 by press fitting or the like. 6 is the N pole and S pole on the yoke 16.
A first magnet whose poles are mounted opposite each other forms a magnetic circuit together with the yoke 16.

In addition, the rotating magnetic field 7, which is a magnetic field of N pole and S pole, is generated by the throttle valve 2.
．． It rotates together with the throttle valve shaft 3.

Next, FIG. 1 shows the rotating portion of the rotating magnetic field 7.

This will be explained using FIGS. 2 and 3.

Inside the throttle body 1, for example, epoxy type.

A ceramic substrate 11 is removably fixed at the first attachment with screws 12 . moreover.

As shown in FIG. 2, a second magnet 8. The magnetoelectric conversion elements 9 are stacked one on top of the other and are fixed integrally. Here, the second magnet is offset in the rotational direction with respect to the rotating magnetic field 7 at an angle of, for example, 45@, and is fixed at the center of the N and S poles of the first magnet. The magnetoelectric transducer 9 is formed in a planar shape so that its resistance value changes depending on the direction of the magnetic field to be sensed. In addition, the lid 14 is designed to prevent magnetic powder, a-dust, etc. from entering the throttle body from the outside.
The second attachment is fixed to the throttle body 1 with a screw 15. Further, the circuit section 1 fixed to the substrate 11
Reference numeral 0 constitutes a power supply section of the magnetoelectric conversion element 9, an amplification section for amplifying the output voltage, etc., and is composed of a hybrid IC. 19 is a harness for power supply, grounding, and signal output (not shown).

Further, 13 is a grommet that supports the harness 19.

Furthermore, a composite magnetic field 17 is formed by the rotating magnetic field 7 of the first magnet 6 and the bias magnetic field 18 of the second magnet 8.

Then, the composite magnetic field 17 changes according to the deviation of the rotating magnetic field 7.

Therefore, the rotational direction of the composite magnetic field 17 sensed by the magnetoelectric transducer 9 is determined by the throttle valve 2. It changes as the throttle valve shaft 3 rotates.

By the way, the magnetoelectric conversion element 9 has a deposited three-terminal structure in which the resistance value changes anisotropically depending on the angle formed between the magnetic field direction and the current direction, and the resistance value of this element is parallel to the pattern surface of the element. It changes depending on the strength and direction of the magnetic field.

Next, the operating principle of the magnetoelectric transducer 9, its equivalent circuit, and the output waveform of the magnetoelectric transducer 9 with respect to the rotational direction of the magnetic field will be explained using FIGS. 4 to 6, respectively. As shown in FIG. 4, the first magnetoelectric transducer R^ and the second magnetoelectric transducer Rn are arranged orthogonally to each other, and the orthogonal common end is used as an output end, and the other end is connected to the power source Vc. is connected to. The three-terminal element (a+bt
When the rotating magnetic field 7 is applied to the first magnetoelectric transducer R^ and the second magnetoelectric transducer Ra in C), the output voltage Vo at point b is expressed by the following equation (1).

R^+Ra However, R^==Rxsin"θ+Rycos"θ
・(2) Ra=Rxcos”θ+Ry sin”θ
-(3), and θ is the electric current and the rotating magnetic field 7
angle formed by

Rx is the resistance value when the electric current wire and the rotating magnetic field 7 are orthogonal to each other, R
yl! This is the resistance value when the electric current wire and the rotating magnetic field 7 are parallel.

Furthermore, by substituting equations (2) and (3) into equation (1) to simplify it, the following equation (4) or (5) can be obtained.

Vo"A-Bcos2θvc...(5
) Here, the coefficient A depends on the power supply voltage Vc, and the coefficient B depends on the material of the element. In addition, as shown in FIG.
, that is, the throttle valve 2. It is controlled by the rotational opening degree of the throttle valve shaft 3 and the characteristics of the output voltage Vo. From the above, it can be seen that when the throttle makes one revolution (360'), the output becomes a two-cycle sine wave.

FIG. 7 shows the composite magnetic field 17 created by the rotating magnetic field 7 and the bias magnetic field 18, and FIG. 8 shows the magnetoelectric conversion element 9 created by the composite magnetic field 17.
The output waveform of is shown. According to FIG. 7, with respect to the angle θ=O″′ formed by the rotating magnetic field 7, in this embodiment, the bias magnetic field 18 is applied at a position of θ=45″. The magnetic field sensed by the magnetoelectric transducer 9 is a composite magnetic field 17 consisting of the rotating magnetic field 7 and the bias magnetic field 18. Assuming that the rotating magnetic field is Hr and the bias magnetic field is Hb, the composite magnetic field Hj is given by equation (6).

IH gate +=fi ding τ stone 17F (6) In this embodiment, 1Hrl=lHbl. As the rotating magnetic field 7 rotates, the composite magnetic field 17 also rotates in the same direction as the rotating magnetic field. In the case of this embodiment, in the clockwise direction, for example, when the rotating magnetic field 7 has a deviation of 0 (Q position), the combined magnetic field 17 is 45
@/2 and becomes the H position. Similarly, the rotating magnetic field 7 is P
When it is at the Q position, the composite magnetic field 17 is at the J position and
Furthermore, Figure 8 shows the 'synthetic magnetic field 1
7 shows the displacement of the output waveform Vo of the magnetoelectric transducer 9 with respect to 7. Here, the throttle rotates once (360°)
It is characterized in that a sine wave output of one period can be obtained when As mentioned above, the rotating magnetic field 7 is generated by the throttle valve 2.
It rotates in synchronization with the throttle valve shaft 3. Actually, throttle valve 2.
Since the rotation range of the throttle valve shaft 3 is approximately 0 to 90 degrees, if the 0 degree position of the throttle valve 2 is set to the Q position, the linear output Vo between θ and Q in the range of θ = 0 to 90 degrees corresponds to the rotational opening degree of the throttle valve 2. Also, if the 00 position is set to the P position, P-
Curve output V between R. corresponds to the rotational opening degree of the throttle valve 2.

In this embodiment, the first magnet 6 is arranged on the rotating throttle valve shaft 3 side, but conversely, the magnetoelectric conversion element 9 and the second magnet 8 may be arranged on the throttle valve shaft 3 side.

According to an embodiment of the invention, the throttle valve 2 and the throttle valve shaft 3
By using the composite magnetic field 17 formed by the rotating magnetic field 7 generated in synchronization with the rotation of the motor and the bias magnetic field 18, one cycle of sine wave output is obtained when the throttle rotates once (360°). be able to. In other words, in the range of 0 to 90 degrees per rotation, a linear output or a curved output is obtained with respect to the opening, so no matter which characteristic is used, the accuracy (resolution ). Furthermore, since the detection part is non-contact and embedded in the throttle body, there is no momentary interruption of the output signal, resulting in high accuracy and excellent reliability.

〔Effect of the invention〕

According to the present invention, the magnetoelectric transducer whose resistance value changes depending on the direction of the magnetic field or the strength of the magnetic field is connected to the rotating magnetic field of the first magnet synchronized with the rotation of the throttle valve and the throttle valve shaft, and the newly installed magnetoelectric transducer. By sensing the composite magnetic field formed by the bias magnetic field of the second magnet and the bias magnetic field of the second magnet, one period of a sine wave output is generated when the throttle valve shaft makes one rotation (360 degrees).

Therefore, in the range of rotational opening of the throttle valve from 0 to 90', a linear output or a curved output can be obtained depending on the opening degree, so no matter which characteristic is used, it is possible to obtain a linear output or a curved output in the low opening degree range. The accuracy (resolution) in is improved.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of the main part of FIG. 3 representing the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a sectional view of the throttle body.
Figure 4 is a diagram of the operating principle of the magnetoelectric conversion element, Figure 5 is an equivalent circuit diagram of Figure 4, Figure 6 is an output waveform diagram of the magnetoelectric conversion element with respect to the rotating direction of the magnetic field, and Figure 7 is the rotating magnetic field and bias magnetic field. Figure 8 is a diagram of the output waveform of the magnetoelectric transducer for the composite magnetic field. 1... Throttle body, 2... Throttle valve, 3...
Throttle valve shaft, 6... First magnet, 7... Rotating magnetic field, 8
...Second magnet, 9...Magnetoelectric conversion element, 17...
Composite magnetic field, 18...bias magnetic field.

Claims (1)

[Scope of Claims] 1. A throttle valve fixed to one end of the throttle valve shaft of an internal combustion engine by a magnetoelectric conversion element that senses a magnetic field generated by a first magnet fixed to one end of the throttle valve shaft. In a throttle sensor that non-contact detects the degree of rotational opening of the first magnet, the bias is biased toward the rotational direction with respect to the rotating magnetic field generated by the first magnet, and whose center is aligned with the center of the first magnet. A throttle sensor characterized in that a second magnet for generating a magnetic field is provided, and a signal supplied to the magnetoelectric conversion element is obtained from a composite magnetic field formed from the rotating magnetic field and the bias magnetic field. 2. The throttle sensor according to claim 1, wherein the magnetoelectric conversion element is a ferromagnetic magnetoresistive element whose output signal changes depending on the direction of the magnetic field. 3. The throttle sensor according to claim 1, wherein the magnetoelectric conversion element is a ferromagnetic magnetoresistive element whose output signal changes depending on the strength of the magnetic field. 4. The throttle sensor according to claim 1, wherein the magnetoelectric conversion element generates an output signal that is substantially a sine wave of one cycle when the throttle valve shaft rotates once. . 5. The throttle sensor according to claim 1, wherein the magnetoelectric conversion element is integrally formed with the second magnet and is removably fixed within the throttle body.