JPH0526610A - Throttle position sensor - Google Patents

Abstract

PURPOSE:To provide a throttle position sensor having high durability and capable of securing detection precision without individually compensating the output drift. CONSTITUTION:A pair of permanent magnets 15, 16 are arranged face to face across the rotary shaft Z of a shaft 5 at the tip of the shaft 5 rotated in conjunction with the rotary shaft Z of a throttle valve, and a pair of permanent magnets 17, 18 formed into a circular arc shape are provided in parallel on a circular arc centering on the rotary shaft Z of the shaft 5. The permanent magnets 15, 16 form the magnetic path from one face to the other face, and a throttle aperture detecting hold element 28 is provided on the magnetic path. The permanent magnets 17, 18 form the magnetic path between side faces parallel with the face perpendicular to the rotary shaft Z, and a hole element 22 detecting the idle state that the throttle valve is fully closed from the boundary position of both magnets 17, 18 is provided on the magnetic path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle position sensor attached to a rotary shaft of a throttle valve of an internal combustion engine for detecting a throttle opening and an idle operation of the internal combustion engine in which the throttle valve is in a fully closed state.

[0002]

2. Description of the Related Art Conventionally, as a throttle position sensor for individually detecting an opening of a throttle valve of an internal combustion engine and an idle operation of the internal combustion engine in which the throttle valve is fully closed, for example, Japanese Utility Model Laid-Open No. 59-41708. A variable resistor type throttle position sensor disclosed in Japanese Patent Laid-Open No. Hei 2 (1999) -242242 by sliding contacts of a conductive resin resistor.
A non-contact type throttle position sensor based on a magnetic detection method disclosed in Japanese Patent No. 298802 is known.

[0003]

However, since the variable resistor type throttle position sensor described above slides the contacts on the conductive resin resistor, the sliding portion is deteriorated with use. However, there was a problem that the durable life was limited.

On the other hand, the above-mentioned magnetic detection type throttle position sensor has a very high durability because it is a non-contact type and can solve the above problems. However, the conventional one uses a magnetoresistive element. Therefore, it is necessary to perform temperature compensation or the like on the detection characteristic for each sensor, which causes a problem of poor productivity.

That is, first, since the magnetoresistive element has low detection sensitivity, an amplification circuit for amplifying the detection signal is used.
Due to the amplification of this detection signal, the drift of the detection characteristics due to factors such as temperature is also amplified, and the output drift of the throttle position sensor becomes large. On the other hand, the magnetoresistive element detects the direction of the magnetic field by a pair of patterns formed of Ni-Co ferromagnetic alloy thin films or the like in directions orthogonal to each other, but it is difficult to form each pattern under exactly the same conditions. Therefore, the drift is different for each element. Therefore, in the conventional non-contact type throttle position sensor using the magnetoresistive element as described above, in order to secure the detection accuracy, it is necessary to perform temperature drift compensation for each sensor, etc. Sex decreases.

The present invention has been made in view of these problems, and an object thereof is to provide a throttle position sensor having high durability and capable of ensuring detection accuracy without individually compensating for output drift. .

[0007]

SUMMARY OF THE INVENTION That is, the present invention, which has been made to achieve the above object, detects an opening of a throttle valve of an internal combustion engine and an idle operation of the internal combustion engine in which the throttle valve is fully closed. A throttle position sensor, which includes a shaft that rotates in conjunction with the throttle valve, and is composed of a pair of permanent magnets arranged at the tip of the shaft so as to face each other with the rotation axis of the shaft interposed therebetween. An opening detection magnet that forms a magnetic path from the facing surface to the facing surface of the other magnet, and a pair of arc-shaped permanent magnets that are arranged in parallel along an arc centered on the rotation axis of the shaft, While providing an idle detection magnet that forms a magnetic path from a side surface parallel to a surface orthogonal to the rotation axis of the shaft of one magnet to the same side surface of the other magnet,
Between the pair of permanent magnets constituting the opening detection magnet,
And Hall elements for detecting the direction of the magnetic field in the magnetic path formed by each of the magnets are provided at positions separated from the side surface of the idle detection magnet in the axial direction of the shaft by a predetermined distance. The gist is the characteristic throttle position sensor.

[0008]

In the throttle position sensor of the present invention thus constructed, the opening degree detecting magnet forms a magnetic path with the rotation axis of the shaft sandwiched between them. Therefore, the magnetic field direction in the formed magnetic path is It changes according to the rotation angle of the shaft. For this reason, the rotation angle of the shaft and thus the opening of the throttle valve can be detected by the Hall element provided in the magnetic path formed by the opening detection magnet.

On the other hand, the idle detection magnet is composed of a pair of arc-shaped permanent magnets arranged side by side along an arc centered on the rotation axis of the shaft, and is parallel to the plane orthogonal to the rotation axis of the shaft of each magnet. Since a magnetic path is formed between the side surfaces, the direction of the magnetic field is reversed at the boundary between both magnets at the upper portion of the side surface.
Therefore, the hall element provided on the upper portion of the side surface can detect a predetermined rotational position of the boundary portion of both magnets, and further the shaft, and by making this position correspond to the fully closed position of the throttle valve, The idle operation of can be detected.

As described above, according to the present invention, since the opening of the throttle valve and the idle operation of the internal combustion engine are detected by the two Hall elements, the detection characteristics such as temperature compensation are corrected for each sensor as in the conventional case. You don't have to. That is, first of all, since the Hall element has high detection sensitivity, it is not necessary to greatly amplify the detection signal, and there is little variation in the detection characteristics of each element, and the output drift is not affected by the magnetic field strength, so the output signal level is large. The more the detection error due to the output drift becomes smaller. Therefore, if the output signal level of the Hall element is increased by increasing the strength of the magnetic field applied to the Hall element, it is possible to reduce the detection error due to output drift, and the detection characteristics of each sensor as in the past. There is no need to make corrections.

For this purpose, as described in claims 2 and 3, the maximum magnetic field strength at the Hall element position of the magnetic path formed by the opening detecting magnet is set to 0.15 Tesler or more. Preferably, the maximum magnetic field strength at the Hall element position of the magnetic path formed by the idle detection magnet,
It is preferably 0.12 Tesler or more.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a sectional view showing the internal structure of the throttle position sensor of the present embodiment, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is taken along the line BBA in FIG. A sectional view and FIG. 4 are bottom views of the throttle position sensor.

As shown in FIGS. 1 to 4, the throttle position sensor of this embodiment includes a hollow housing 1 having a cylindrical bearing mounting portion 1a formed in the center thereof. A bearing 3 having a concentric shape and a different diameter is press-fitted and fixed to the bearing mounting portion 1a.
The shaft 5 is rotatably accommodated. A lever 7 for receiving the rotation of the throttle valve is fixedly provided at the lower end portion of the shaft 5 shown in FIG. 1, and a coil spring 9 is provided between the lever 7 and the housing 1. As shown in FIG. 4, both ends 9a and 9b of the coil spring 9 are
The coil spring 9 is locked to the protrusion 1b formed on the housing 1 and the protrusion 7a formed on the lever 7, respectively, and the coil spring 9 is rotated in conjunction with the throttle valve.
And the shaft 5 in the closing direction of the throttle valve (direction of arrow C).

On the other hand, a wave-like elastic washer 11 is provided between the upper end of the bearing 3 in FIG. 1 and the shaft 5 so as to prevent looseness in the Z direction shown in FIG. In addition, a stepped hole 5a is formed at the center of the upper end of the shaft 5 in FIG.
b is formed. As shown in FIG. 3, in the stepped hole 5a, a pair of permanent magnets 15 and 16 made of a rare earth element such as Nd-Fe-B system is disposed so as to face each other, and in the collar portion 5b,
Similarly, arc-shaped permanent magnets 17 and 18 made of a rare earth element such as Nd-Fe-B system are arranged side by side on an arc centered on the rotation axis of the shaft 5.

The permanent magnets 15 and 16 compose the above-described opening degree detecting magnet, and are magnetized so as to form a magnetic path from one magnet surface toward the opposing magnet surface. Further, the permanent magnets 15 and 16 are fixed to the step portion of the stepped hole 5a by magnetic force and adhesion, so that the permanent magnets 15 and 16 are attached so as to be floated by a certain distance from the bottom of the stepped hole 5a.

On the other hand, the permanent magnets 17 and 18 compose the above-mentioned idle detecting magnet, and between the side surfaces parallel to the plane orthogonal to the rotation axis (Z axis shown in FIG. 1) of the shaft 5 of both magnets. In order to form a magnetic path, as shown in FIG. 3, the magnets 17 and 18 are magnetized in the side direction thereof, and the different magnetic pole surfaces S and N are fixed to the flange portion 5b by magnetic force and adhesion. Has been done.

Next, above the permanent magnets 15 to 18 in FIG. 1, a non-magnetic conductive material having a protrusion 20a formed in the center and a mounting hole 20b (shown in FIG. 2) for mounting the housing 1 in the periphery is formed. The case 20 that is formed by mounting the mounting hole 20b on the protrusion 1c of the housing 1 and caulking it by heat
It is fixed to the housing 1. In the case 20, the hall element 22, the circuit elements 23 and 24, the terminal 26 are mounted, and the printed circuit board 30 in which the resin collar 29 housing the hall element 28 is fixed by heat staking or the like, It is fixed by adhesion.

Here, the collar 29 is for fixing and positioning the Hall element 28 to the printed circuit board 30, the inner shape is the same as the resin mold outer shape of the Hall element 28, and the outer shape is the protrusion of the case 20. It has the same shape as the inner shape of the portion 20 a and has a protrusion for attachment to the printed circuit board 30.

The hall element 22 is a printed circuit board 30.
Is provided at a position facing the magnets 17 and 18 on the back surface (surface on the shaft 5 side), and a steel ball 32 having a diameter of 1 to 5 mm is provided 0 to 2 mm above the center thereof.
The steel ball 32 is for guiding the magnetic field formed by the magnets 17 and 18 to the Hall element 22. For example, a conical magnetic piece having a diameter of 1 to 10 mm and a height of 1 to 10 mm is used. May be.

Further, the positions of the Hall elements 22 and 28 are
The Hall element 2 at the center is determined by the dimensional accuracy of the housing 1, the case 20, the printed circuit board 30, and the collar 29.
8 is designed so that the centers of the permanent magnets 15 and 16 are the centers of the Hall element chips on the rotation axis of the shaft 5 and that the magnetic fields of the X and Y components shown in FIG. , The other Hall element 22 is a permanent magnet 17, 1
8 at a certain distance above in FIG. 1, when the throttle valve is at the position of the idle boundary opened from the fully closed position, the Hall element chip center is on the boundary of the pair of permanent magnets 17 and 18, and The magnetic field of the Z component shown in FIG. 1 is designed to be in a magnetically sensitive position.

Further, as the hall elements 22 and 28, hall elements (THS106A and THS112) manufactured by Toshiba Corporation having an output of 1150 mV (when applying 1 T and 5 mA) and an output drift of 4 mV are used, and permanent magnets 15 and 16 are used. Is the Hall element 28
The permanent magnets 17 and 18 are magnetized so that the maximum magnetic field strength of the X and Y components corresponding to the rotation of the shaft 5 at the position becomes 0.20 Tesler (hereinafter, simply referred to as T).
It is magnetized so that the maximum magnetic field strength of the Z component corresponding to the rotation of the shaft 5 at the position of the Hall element 22 is 0.15T.

Next, four feedthrough capacitors 34 are electrically connected and fixed to the case 20 by soldering or the like. The feedthrough capacitor 34 includes four terminals 26 mounted on the printed circuit board 30 and four connector terminals 36 embedded in the connector portion 35 of the housing 1.
To connect the circuit elements 23 and 24 to the circuit board 23 and 24, respectively, to externally supply power to the circuit elements 23 and 24 to operate the circuit elements 23 and 24, and to obtain a detection signal obtained by this operation. Can be taken out.

Further, a rubber packing 38 is provided in the housing opening 1d above the case 20 in FIG. 1, and a magnetic material cover 39 is further provided on the rubber packing 38 to heat crimp the periphery of the housing opening 1d. As a result, these parts are fixed. In addition, FIG.
The upper part of the rubber packing 38 is filled or coated with a moisture-proofing agent 40 such as a low stress gel or a Humi-Seal.
The inside of the case 20 sealed by is protected from moisture. Further, as shown in FIG. 3, mating attachment portions 1e in which the bushes 41 are embedded are formed at two locations on the outside of the housing 1 that are symmetrical with respect to the rotation axis of the shaft 5.

In the throttle position sensor of this embodiment constructed as described above, the lever 7 is connected to the rotary shaft of the throttle valve, and the shaft 5 is rotated with the rotation thereof.
Rotates. Then, with this rotation, the pair of permanent magnets 1
Since 5 and 16 rotate around the Hall element 28, the magnetic field direction with respect to the magnetic sensitive surface of the Hall element 28 changes as shown in FIG.

As a result, the output VH from the Hall element 28
Changes according to the following equation (1): VH = VA.sin θ (1) As shown in FIG. 5B, the shaft 5 moves from −90 ° to +9.
While rotating to 0 °, it continuously changes on the sine wave from −VA to + VA.

Further, in the throttle position sensor of the present embodiment, the permanent magnet 1 is accompanied by the rotation of the shaft 5.
7 and 18 rotate as shown in FIG.
At the boundary surface between 7 and 18, the magnetic field direction with respect to the magnetic sensitive surface of the Hall element 22 is reversed. Therefore, the output VH from the Hall element 22 changes according to the following equation (2), and VH = θ · VB / θA (2) As shown in FIG. 6B, the shaft 5 moves from −θA ° to + θA
While rotating to °, it changes continuously from -VB to + VB with a constant slope.

Next, the detection circuit for operating the Hall elements 22 and 28 which can obtain such output characteristics to take out the detection signal depends on the circuit patterns formed on the circuit elements 23 and 24 and the printed circuit board 30. , Is constructed as shown in FIG. That is, the detection circuit of the throttle position sensor of this embodiment is composed of the temperature sensitive resistor R1 having positive temperature characteristics and the resistors R2 to R6, and generates the reference voltage V1 for driving the Hall elements 22 and 28. A driving circuit 52 including a temperature compensating circuit 50, an operational amplifier OP1 and a resistor R7, which drives the Hall element 28 with a constant current based on the reference voltage V1 from the temperature compensating circuit 50, operational amplifiers OP2 and OP3, and resistors R9 to R11. And a buffer circuit 54 that allows each output terminal voltage of the Hall element 28 to pass, an operational amplifier OP4, a transistor TR1, and resistors R12 to R18. Each output terminal voltage that has passed through the buffer circuit 54 is differentially amplified. Differential amplifier circuit 5
6. A reference voltage generation circuit 58 which includes an operational amplifier OP5 and resistors R19 and R20, and which increases the amplified output potential of the differential amplifier circuit 56 by a reference voltage V2 obtained by dividing the power supply voltage Vcc by the resistors R19 and R20. A filter circuit 6 including a capacitor C1 and resistors R21 and R22, which outputs the amplified output from the differential amplifier circuit 56 to the outside as a throttle opening signal VL representing the opening of the throttle valve.
0, an operational amplifier OP6 and a resistor R23, and the Hall element 2 based on the reference voltage V1 from the temperature compensation circuit 50.
2, a drive circuit 62 for driving constant current, an operational amplifier OP7 and resistors R24 to R27, a differential amplifier circuit 64 for differentially amplifying each output terminal voltage of the Hall element 22, an operational amplifier OP8 and a resistor R28, R29, a reference voltage generating circuit 66 for increasing the amplified output potential of the differential amplifier circuit 64 by a reference voltage V3 obtained by dividing the power supply voltage Vcc by resistors R28, R29, an operational amplifier OP9 and a resistor R.
Comparing the amplified output from the differential amplifier circuit 64 with the reference voltage V4 obtained by dividing the power supply voltage VCC by the resistors R30 and R31,
And the switching transistor TR2 and the resistor R3
5, R36, and the comparison result by the comparator 68 indicates that the throttle valve is fully closed (that is, idle operation).
The output circuit 70 outputs the idle signal VI indicating whether or not to the outside.

Therefore, as shown in FIG. 8, the detection circuit outputs a throttle opening signal VL which changes according to the opening of the throttle valve and an idle signal VI which is inverted at the boundary where the opening of the throttle valve becomes zero. It will be output. In FIG. 7, capacitors C2 and C3 are noise removing capacitors.

The temperature compensating circuit 50 of this embodiment comprises a temperature sensitive resistor R1 and resistors R2, R3 and R4 to form a bridge circuit, one end of which is applied with a power supply voltage VCC and the other end of which is grounded. (Gnd), and the reference voltage V1 is generated by detecting the circuit voltage division by the resistors R5 and R6. This is because the inclination of the reference voltage V1 with respect to the temperature can be freely set in accordance with the temperature characteristics of the Hall elements 22 and 28.

That is, the temperature compensating circuit which has been conventionally used is, as shown in FIG. 9A, a temperature sensitive resistor r1 and a resistor r.
Since the resistors r2 and r3 are simply connected in series, the slope of the reference voltage V1 with respect to temperature can be set by the resistance values of the resistors r2 and r3, but the resistors r2 and r3 cannot be set. Since it is finite, there is no freedom in setting the inclination, and it was difficult to match the inclination with the temperature characteristics of the Hall element. Therefore, in this embodiment, the temperature compensating circuit is configured by the bridge circuit as described above, so that the resistance value of each resistor is selected.
In the range D shown in (b), the slope of the reference voltage V1 with respect to the temperature can be set to infinity so that the reference voltage V1 can be freely set in accordance with the temperature characteristics of the Hall elements 22 and 28. I did it.

Further, in this embodiment, after the voltage difference between the output terminals of the Hall element 22 is amplified by the differential amplifier circuit 64, the idle signal VI is obtained by comparing with the reference voltage V4 by the comparator 68. However, this is to improve the determination accuracy of the idle operation.

That is, when a conventional determination circuit such as a proximity switch using a Hall element is applied to idle determination, FIG.
As shown in (a), the output terminal voltage of the Hall element 22 is
It is input to the comparator including the operational amplifier OP11 and the resistors r4 and r5.
As shown in FIG. 0 (b), since the output of the Hall element 22 (the straight line A shown in the figure) is directly compared, when the threshold level indicated by the alternate long and short dash line in the figure changes due to a voltage change or the like, the angular position at which the comparator output is inverted is also changed. △ θ A fluctuates. Therefore, in the present embodiment, by amplifying the Hall element output using the differential amplifier circuit 64, the slope of the input signal to the comparator 68 is made large as shown by the straight line B in the figure, which causes fluctuations in the threshold level. The associated detection error is ΔθA
It has improved from ΔθB to ΔθB to ensure the determination accuracy of idle operation.

As described above, in the throttle position sensor of this embodiment, the two hall elements 22 and 28 detect the opening of the throttle valve and the idle operation of the internal combustion engine in which the throttle valve is fully closed. It is configured. Since the maximum magnetic field strength corresponding to the rotation of the shaft 5 at the position of the Hall element 28 is set to 0.20T, the ratio of the output drift to the Hall element output VA shown in FIG.
The detection error Δθ1 of the rotation angle due to the output drift ΔVH (4 mV in this embodiment) is 1.0 ° as expressed by the following equation (3).
Therefore, the angular accuracy is 1.5 ° even if the assembly error is taken into consideration.
Can be achieved within.

Δθ1 = sin−1 (ΔVH / VA) = sin−1 {ΔVH / (VH · B1)} = sin−1 {4 / (1150 · 0.20)} = 1.0 ° (3) However, this equation (3) is an equation obtained by modifying the above equation (1), where VH is the rated output of the Hall element (at 1T, 5mA applied) and B1 is the maximum at the Hall element 28 position. The magnetic field strength is shown.

Since the maximum magnetic field strength corresponding to the rotation of the shaft 5 at the position of the Hall element 22 is set to 0.15T, the ratio of the output drift to the Hall element output VB shown in FIG. The detection error Δθ2 of the idle operation due to the output drift ΔVH (4 mV in this embodiment) of the element 22 is 0.23 ° as in the following formula (4), and the angle accuracy is 0.3 ° even if the assembly error and the like are considered. Can be achieved within.

Δθ2 = (ΔVH · θA) / VB = (ΔVH · θA) / (VH · B2) = {(4 · 10) / (1150 · 0.20)} = 0.23 ° ( 4) However, this equation (4) is an equation obtained by modifying the above equation (2), and B2 is the maximum magnetic field strength at the position of the Hall element 22, θ
A represents the values obtained from the experimental data of FIG. 6 (b), respectively.

Therefore, according to the throttle position sensor of this embodiment, it is not necessary to correct the detection characteristic such as temperature compensation for each sensor in order to secure the detection accuracy as in the conventional case, and the productivity is improved. Can be improved. In this embodiment, the maximum magnetic field strength at the position of the Hall element 28 used for detecting the throttle opening is 0.20T and the maximum magnetic field strength at the position of the Hall element 22 used for detecting the idle operation is 0.15T. By further increasing the maximum magnetic field strength at each Hall element position, the influence of the output drift of the Hall element can be reduced and the detection accuracy can be further improved. Further, this value does not necessarily have to be as in the present embodiment, and depends on the characteristics of the Hall element used,
As a result of an experiment using various Hall elements, the maximum magnetic field strength at the position of the Hall element 28 is 0.15 T or more,
It has been found that if the maximum magnetic field strength at the position is set to 0.12T or more, the angle accuracy of the throttle position sensor can be secured.

Next, in this embodiment, each Hall element 2
Permanent magnet 15 for forming a magnetic path at positions 2, 28
A permanent magnet made of a rare earth element such as Nd-Fe-B is used for No. 18. This is because the permanent magnet made of a rare earth element can obtain a large magnetic field strength. The throttle position sensor can be made smaller and lighter in size.

Further, in this embodiment, since the steel ball 32 for guiding the magnetic field is provided in the vicinity of the hall element 22, the position of the hall element 22 by the permanent magnets 17 and 18 is larger than that in the case where the steel ball 32 is not provided. The maximum magnetic field strength can be increased,
This also makes it possible to reduce the size and weight of the throttle position sensor by reducing the size of the permanent magnet used. As a result of the experiment, when the steel ball 32 having a diameter of 1.5 mm is used as in this embodiment, the maximum magnetic field strength at the position of the hall element 22 is increased by 30%, and the diameter is 6 mm and the height is 6 m.
It was found that the maximum magnetic field strength at the position of the Hall element 22 was increased by 55% by using the conical magnetic piece of m.

Furthermore, in the present embodiment, the Hall element 22,
Printed circuit board 3 on which 28, circuit elements 23, 24, etc. are mounted
0 is housed in a case 20 made of a non-magnetic conductive material, and this case 20 is further housed in a housing 1 by a cover 39 made of a magnetic material, and the terminal 2 of the printed circuit board 30 is accommodated.
6 and the connector terminal 36 are connected by the feedthrough capacitor 34, the case 20 and the cover 39 shield electromagnetic waves from the outside, and the feedthrough capacitor 34 can prevent the electromagnetic wave from entering from the connector terminal 36. The opening degree of the throttle valve and the idle operation can be detected without being affected by electromagnetic waves from the outside, which also improves the detection accuracy.

Further, in this embodiment, since the hall element 28 is housed in the collar 29 and fixed to the printed circuit board 30, the hall element 28 can be easily positioned. Further, the collar 29 can prevent the lead of the Hall element 28 from twisting in the shaft rotation direction due to temperature / vibration stress due to long-term use, and therefore the durability of the throttle position sensor can be secured.

Further, in the present embodiment, since the shaft 5 is fixed to the housing 1 via the bearing 3, the play of assembling the shaft 5 in the rotating direction can be reduced by the bearing 3, and some external force is applied to the lever 7. It is possible to reduce the fluctuation of the Hall element output caused by the shaft 5 caused by this.

Here, in the above embodiment, the resin collar 29 is used for assembling the hall element 28 to the printed board 30, but as shown in FIGS. 11 to 13, instead of the collar 29, a non-magnetic material is used. The Hall element 28 may be housed in the holder 71 made of a conductive material, and the holder 71 may be fixed to the printed circuit board 30. 11 is a sectional view showing the internal structure of the throttle position sensor using the holder 71, FIG. 12 is a sectional view taken along the line EE in FIG. 11,
FIG. 3 is a sectional view taken along the line FF in FIG.

In this case, the intrusion of electromagnetic waves is prevented by the holder 7
Therefore, the flat case (i.e., no projection) case 75 in which the projection 20a of the case 20 of the above-described embodiment is provided with the hole 73 for inserting the holder 71 is provided.
Can be used, and the case 75 can be easily manufactured and handled. Further, as shown in FIG. 13, by forming a latch 71a on the holder 71 and pressing the Hall element 28 against the wall of the holder 71 to fix it, the Hall element 28 can be easily assembled to the printed circuit board 30. In addition to the above, the effect of preventing the twisting of the lead wire due to the temperature / vibration stress associated with the long-term use of the Hall element 28 can be made equal to or greater than the collar 29 of the above-described embodiment.

In addition, in the throttle position sensor of this embodiment shown in FIGS. 11 to 13, the above-described portion and the point that the case 75 and the printed circuit board 30 are fixed to the housing 1 by the screw bolt 77, It is the same as the throttle position sensor of the above-mentioned embodiment except for the difference from the above-mentioned embodiment, and therefore the further description is omitted.

[0046]

As described above in detail, according to the throttle position sensor of the present invention, since it is a non-contact type sensor, it is possible to ensure durability and to use it like a conventional non-contact type sensor. Since it is not necessary to perform temperature compensation of the output drift for each sensor in order to ensure the detection accuracy, the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an internal configuration of a throttle position sensor of an embodiment.

FIG. 2 is a cross-sectional view taken along the line AA in FIG.

3 is a cross-sectional view taken along the line B-B-A in FIG.

FIG. 4 is a bottom view of a throttle position sensor.

FIG. 5 is an operation explanatory diagram illustrating a detection operation of a throttle opening degree by a hall element 28.

FIG. 6 is an operation explanatory diagram illustrating an idle detection operation by the hall element 22.

FIG. 7 is an electric circuit diagram showing a configuration of a detection circuit.

FIG. 8 is an explanatory diagram showing detection signal characteristics obtained by the detection circuit of FIG.

9 is an explanatory diagram of the operation of the temperature compensation circuit in FIG.

FIG. 10 is an operation explanatory diagram of the idle determination circuit in FIG. 7.

FIG. 11 is a cross-sectional view showing an internal configuration of a throttle position sensor using a holder 71.

12 is a cross-sectional view taken along the line EE in FIG.

13 is a cross-sectional view taken along the line FF in FIG.

[Explanation of symbols]

1 ... Housing 3 ... Bearing 5 ... Shaft
7 ... Lever 15, 16, 17, 18 ... Permanent magnet 20 ... Case 22, 28 ... Hall element 26 ... Terminal 29
... Color 30 ... Printed circuit board 32 ... Steel ball 34 ... Through-through capacitor 36 ... Connector terminal 38 ... Rubber packing
39 ... Cover 50 ... Temperature compensation circuit 52, 62 ... Drive circuit 54
... buffer circuits 56, 64 ... differential amplifier circuits 58, 66 ... reference voltage generation circuit 60 ... filter circuit 68 ... comparator 70 ...
Output circuit 71 ... Holder 75 ... Case

Claims (3)

[Claims] 1. A throttle position sensor for detecting an opening of a throttle valve of an internal combustion engine and an idle operation of the internal combustion engine in which the throttle valve is in a fully closed state, comprising a shaft which rotates in conjunction with the throttle valve. , An opening degree detection that comprises a pair of permanent magnets arranged at the tip of the shaft so as to face each other with the axis of rotation of the shaft interposed therebetween, and forms a magnetic path from the facing surface of one magnet to the facing surface of the other magnet Magnet, and a pair of arc-shaped permanent magnets arranged side by side along an arc centered on the rotation axis of the shaft. From one side surface of the magnet parallel to the surface orthogonal to the rotation axis of the shaft to the other An idle detection magnet that forms a magnetic path on the same side of the magnet, and between the pair of permanent magnets that form the opening detection magnet,
And Hall elements for detecting the direction of the magnetic field in the magnetic path formed by each of the magnets are provided at positions separated from the side surface of the idle detection magnet in the axial direction of the shaft by a predetermined distance. A characteristic throttle position sensor. 2. A magnetic path formed by the opening detection magnet,
The throttle position sensor according to claim 1, wherein the maximum magnetic field strength at the position of the Hall element is 0.15 Tesler or more. 3. The maximum magnetic field strength of the magnetic path formed by the idle detection magnet at the position of the Hall element is 0.12.
The throttle position sensor according to claim 1, wherein the throttle position sensor is a Tesler or more.