JPH07317571A - Carburetor opening sensing device - Google Patents

Abstract

PURPOSE:To provide a carburetor opening sensing device which can work well with smaller size of construction through simplification of the sensing mechanism, allows suppression of the costs, and accomplishes enhancement of the sensing accuracy. CONSTITUTION:An opening sensing device for a carburetor 1 is formed from a carburetor body 2 having venturi passage 6 and a valve chamber 7 formed in such a way as opening to the passage and a variable area valve 9 arranged in the valve chamber 7 slidably and varying the area of the venturi passage, wherein a magnet is secured to the valve 9. Magnetic sensor 28a-28c to emit the outputs in accordance with the intensity of the magnetic field generated by the magnet 25 are installed in that position on the outer surface of a bulkhead 2d to form the valve chamber 7 which can be situated opposingly to the magnet 25, and a sensor position adjusting means is furnished to vary the sliding direction and position of the valve 9 of the sensors 28a-28c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening detecting device for detecting a throttle valve opening of a carburetor equipped with a direct acting throttle valve.

[0002]

2. Description of the Related Art For example, an engine of a motorcycle or the like is equipped with an ignition timing control device in order to improve output, fuel consumption and purify exhaust gas. The ignition timing control device is configured to detect the engine load state from the engine speed and the throttle opening, for example, and control the ignition timing to an ignition timing corresponding to these detected values.

In order to detect the throttle opening in such ignition timing control, when a carburetor having a rotary butterfly valve is conventionally provided, the rotation angle of the butterfly valve is detected by a potentiometer. The method is generally adopted. On the other hand, when the carburetor having a direct-acting piston valve is provided, the axial movement amount of the piston valve is converted into a rotation angle via a rotation mechanism, and this is detected by a potentiometer.

[0004]

However, in the above-described conventional opening degree detection device for the piston valve type carburetor, since it is necessary to separately provide a rotation mechanism for converting the movement amount of the piston valve into a rotation angle, the structure is required. However, there is a problem that the cost is increased due to the increase in the number of parts, and the detection accuracy is likely to be lowered due to the structure that converts the linear movement amount of the piston valve into the rotation angle. .

The present invention has been made in view of the above-mentioned conventional circumstances, and provides a carburetor opening degree detection device which can be downsized with a simple structure, can reduce cost, and can improve detection accuracy. It is an object.

[0006]

In order to achieve the above-mentioned object, the present inventor studied a detection mechanism capable of directly detecting the axial position of a direct acting type variable area valve, and arranged a magnet on the variable area valve. An opening that can realize a simplification and downsizing of the structure by installing a magnetic sensor for detecting the change in the magnetic field strength of the magnet due to the axial movement of the valve at a position facing the magnet on the partition wall of the cab body. A detector was developed.

By the way, in order to improve the detection accuracy of the opening of the variable area valve, that is, the axial position, the accuracy of the arrangement position of the magnetic sensor is extremely important. For example, in the case of a structure in which a board on which a magnetic sensor is mounted is directly mounted in a cab body or housed in a case, the positional accuracy is such that the magnetic sensor is mounted on the board and the board is mounted on the cab body or the case. It is determined by the accumulation of precision. Therefore, it is necessary to increase the accuracy of each attachment, but this method naturally has its limits.

Therefore, according to the invention of claim 1, a cab body having a venturi passage and a valve chamber formed so as to open in the passage, and an area for slidably disposed in the valve chamber and changing a venturi passage area. In a carburetor opening detection device including a variable valve, a magnet is fixed to the area variable valve, and a magnetic sensor that generates an output according to the strength of a magnetic field from the magnet is a partition that forms the valve chamber. It is characterized in that it is provided with a sensor position adjusting means which is attached to the outer surface of the magnet at a position where it can face the magnet, and which changes the attachment position of the magnetic sensor in the sliding direction of the area variable valve.

According to a second aspect of the present invention, the sensor position adjusting means separates the substrate on which the magnetic sensor is arranged and fixed from the magnetic sensor in a direction perpendicular to the sliding direction of the area variable valve. It is characterized in that it is provided with a support pin that pivotally supports a portion on the partition wall and an eccentric cam that swings the substrate about the support pin as a rotation center.

[0010]

In the opening degree detecting device of the present invention, the change in the magnetic field strength of the magnet due to the axial movement of the variable area valve is taken out as an electric signal by the magnetic sensor, and the opening degree of the variable area valve is calculated from the change in the electric signal. The ignition timing of the engine is controlled in accordance with the detected opening.

In the carburetor opening detection device according to the present invention, the detection mechanism is composed of the magnet fixed to the variable area valve and the magnetic sensor fixed to the outer surface of the partition wall of the cab body. The detection mechanism can be simplified as compared with the case where the device is provided, and eventually, downsizing can be supported, and the cost can be reduced by the number of parts. Further, since the magnetic sensor is attached to the partition wall to directly detect the axial position of the variable area valve, the detection accuracy can be improved as compared with the conventional one that converts the axial movement amount into the rotation angle.

Further, in the present invention, the sensor position adjusting means for changing the mounting position of the magnetic sensor in the sliding direction of the variable area valve is provided, and the arrangement position of the magnetic sensor is adjusted by this means. The mounting position of the magnetic sensor can be positioned with high accuracy by absorbing the mounting error of (3), and the detection accuracy can be improved.

A second aspect of the present invention is a specific example of the sensor position adjusting means. In order to position the magnetic sensor by the adjusting means, first, a jig or the like is used to open the variable area valve in a predetermined manner in advance. Degree, for example, set to the first opening slightly opened from the idling position, the substrate on which the magnetic sensor is fixed is swung in the sliding direction of the variable area valve by the eccentric cam, and the magnet is used for the first opening. The substrate is fixed when the magnetic sensors face each other and generate an output signal.

As described above, according to the second aspect of the present invention, the substrate on which the magnetic sensor is arranged and fixed, the support pin that pivotally supports the substrate on the partition wall, and the area of the substrate about the support pin as a rotation center. Since the sensor position adjusting means is composed of the eccentric cam that swings in the sliding direction of the variable valve, the magnetic sensor can be positioned with high accuracy and the detection accuracy can be improved with a simple structure. Further, since the support pin is located at a position separated from the magnetic sensor in a direction substantially perpendicular to the sliding direction of the variable area valve, the deviation of the magnetic sensor in the direction perpendicular to the sliding direction of the valve can be reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views for explaining a carburetor opening detection device according to an embodiment of the present invention. FIG. 1 is a side view of a carburetor to which the device of the present embodiment is applied, and FIG. II of Figure 1
-II sectional view, FIG. 3 is a sectional view of the apparatus of the above-mentioned embodiment, FIG. 4 is a view showing the position adjusting means of the above-mentioned embodiment, and FIG. 5 is a plan view showing a detecting portion of the apparatus of the above-mentioned embodiment.

In the figure, reference numeral 1 is a VM type carburetor to which the apparatus of this embodiment is applied. A float chamber 3 is bolted to an opening on the lower surface of a cab body 2 of the carburetor. Is provided with a wax type auto choke mechanism 4 that opens and closes a starter passage 6a that bypasses the venturi passage 6. A float 5 is vertically swingably arranged in the float chamber 3. The float 5 moves up and down in accordance with the change in the liquid level of the fuel in the chamber 3 to open and close a fuel introduction port (not shown), thereby keeping the liquid level of the fuel in the float chamber 3 constant.

The cab body 2 is made of zinc die-cast, and has a cylindrical main body portion 2a having a venturi passage 6 through which intake air (see mark a in FIG. 1) flows.
Cylinder portion 2b having a valve chamber 7 extending vertically upward from the main body portion 2a and opening into the venturi passage 6
And the body portion 2 so as to be coaxial with the cylinder portion 2b.
Fuel introduction part 2 extending from a into the float chamber 3
and c are integrally formed.

A lid 8 is attached to the upper end opening of the cylinder portion 2b, and a bottomed cylindrical piston valve 9 is axially slidably inserted into the valve chamber 7 of the cylinder portion 2b. There is. This piston valve 9 is made of brass or aluminum alloy, and a resin-made bottomed cylindrical holder 11 is fitted and inserted in the piston valve 9, and the space between the holder 11 and the lid 8 is A spring 10 for urging the valve 9 in the closing direction and pressing and fixing the holder 11 is provided.

The holder 11 has a piston valve 9
E-ring 21a for vertically positioning the jet needle 21 inserted into the above-mentioned fuel introduction portion 2c through the bottom of the
Is pressed against the bottom. Thereby, the holder 11
Is used both for holding the permanent magnet 25 described later and for holding the jet needle 21.

At the bottom of the piston valve 9, one end of a throttle cable 16 is locked, and the cable 16
The extended end of the guide passes through the guide pipe 17 connected to the lid 8 and is connected to an accelerator grip (not shown).
By operating the accelerator grip, the piston valve 9 is moved in the vertical direction to change the passage area of the venturi passage 6 between fully closed and fully opened.

A needle jet 20a is inserted in the upper portion of the fuel introduction portion 2c, and it opens below the piston valve 9 in the venturi passage 6.
Further, the main jet 20 is provided at the lower end of the fuel introducing section 2c.
b is screwed in and opens into the fuel. Within the needle jet 20a, the jet needle 2
1 is inserted so that the piston valve 9 can be moved forward and backward.
The jet needle 21 moves back and forth as the needle jet 20a moves up and down to change the effective opening area of the upper end opening of the needle jet 20a, thereby adjusting the amount of fuel sucked into the venturi passage 6.

A throttle screw 18 for adjusting the idling speed is screwed into a portion of the main body portion 2a which faces the lower end portion of the piston valve 9, and the venturi passage 6 is lubricated in the upper portion thereof. An oil supply port 19 for supplying oil is connected and formed. The lubricating oil supplied from the oil supply port 19 flows down through the groove 9a formed on the side surface of the piston valve 9 and is supplied to the venturi passage 6. Further, an air vent passage 15 is formed in the cab body 2 to connect the space above the float chamber 3 and the outside (see FIG. 1), and the air vent passage 15 keeps the inside of the float chamber 3 at atmospheric pressure. It has become.

When viewed in the piston valve moving direction, the detection main part of the opening degree detecting device of this embodiment is orthogonal to the intake flow a flowing in the venturi passage 6 as shown in FIG. It is arranged on a straight line b passing through the center of 9. The main part of the detection is the permanent magnet 25 located at the upper edge of the piston valve 9, and the partition wall 2 of the cylinder part 2b.
It is composed of magnetic sensors 28a to 28c fixed to the outer surface of d.

The permanent magnet 25 is made of a plastic magnet, is insert-molded integrally with the holder 11, and is exposed to the outside through a slit 9a formed in the upper edge of the piston valve 9. There is.
Here, the outer end surface of the magnet 25 has a slight gap with respect to the inner surface of the partition wall 2d of the cylinder portion 2b. Further, the upper and lower edges of the permanent magnet 25 are formed with edge portions extending in a direction orthogonal to the sliding direction of the piston valve 9. Thereby, the magnetic flux from the permanent magnet 25 can be concentrated on the magnetic sensors 28a to 28c without being diffused, and the detection position accuracy can be improved. The permanent magnet 25 may be directly insert-molded on the upper edge of the piston valve 9, or the permanent magnet 25 may be fixed to a metal holder and the holder may be insert-molded on the side wall of the piston valve.

On the outer surface of the partition wall 2d of the cylinder portion 2b, a sensor chamber 30 that is open to the side is integrally formed, and the sensor unit 26 is accommodated in the sensor chamber 30. This sensor unit 26 has three magnetic sensors 28a, 28b, 28c on the inner surface of the substrate 27 on the partition wall 2d side.
Are fixed by soldering at a predetermined interval in the axial direction of the piston valve 9, and five lead wires 29 are attached to the outer surface of the substrate 27.
And the lead wires 29 corresponding to the magnetic sensors 28a to 28c are connected to the magnetic sensors 28a to 28c through wirings formed on the substrate 27 by patterning.
Each of the magnetic sensors 28a to 28c has a Hall element, MR.
An element or IC is used.

A resin sealing layer 35 is formed in the sensor chamber 30. This is formed by injecting and filling a potting agent made of a room temperature curing epoxy resin into the sensor chamber 30 and drying and solidifying the potting agent. As a result, the sensor unit 26 is resin-sealed, and the lead wires 29 project from the resin sealing layer 35.

The permanent magnet 25 and the magnetic sensor 28a.
As viewed from the moving direction of the piston valve 9 as described above, 28c are arranged on a straight line b which is orthogonal to the axis of the venturi passage 6, that is, the flow direction a of the intake air, and which passes through the center of the piston valve 9. There is. As a result, the vibration of the piston valve 9 causes the permanent magnet 25 and the magnetic sensor 28a.
It avoids changing the gap with 28c. That is, the piston valve 9 easily vibrates in the flow direction of intake air due to the influence of intake pulsation. Therefore, when the permanent magnet 25 and the magnetic sensors 28a to 28c are arranged on the axis of the venturi passage 6, that is, so as to face each other in the vibration direction, the gap between the two 25, 28a to 28c may change. The result detection accuracy may be reduced.

The magnetic sensor 28 of the sensor unit 26
The positions a to 28c can be adjusted in the moving direction of the piston valve 9 by the sensor position adjusting means. This position adjusting means is provided by each of the magnetic sensors 28a to 28a.
The base plate 8c is arranged and fixed in the moving direction of the piston valve 9, a knock pin (support pin) 31 pivotally supporting the base plate 27 on a partition wall 2d in the sensor chamber 30, and a rotatable on the partition wall 2d. And an eccentric cam 32 that comes into contact with the upper end surface of the substrate 27. The knock pin 31 corresponds to the magnetic sensors 28a to 28 of the substrate 27.
It is located at a position away from c in the direction perpendicular to the moving direction of the piston valve 9, and more specifically, it is located on a horizontal line c passing through the center of the magnetic sensor 28b located at the center. It should be noted that the farther the knock pin 31 is from the magnetic sensor 28b, the more the magnetic sensors 28a are adjusted during position adjustment.
It is possible to reduce the deviation in the direction perpendicular to the sliding direction of the valve by 28c. Further, a long hole 34a which is long in the piston valve moving direction is formed in the vicinity of the magnetic sensor 28b of the substrate 27, and the long hole 34a faces the screw hole 33a formed in the partition wall 2d. Furthermore, the above knock pin 3
In the vicinity of 1, a bolt hole 3 having a diameter slightly larger than the fixing bolt 36
4b, 34c are formed, and each bolt hole 34b, 3
4c faces the screw holes 33b and 33c of the partition wall 2d. The board 27 has the fixing bolts 36 and the elongated holes 34.
a, bolt holes 34b, 34c to screw holes 33a to 33c
It is fixed to the gear body 2 by being screwed into.

As a result, the magnetic sensors 28a to 28c are in contact with the outer surface of the partition wall 2d of the cylinder portion 2b,
As the piston valve 9 moves up and down, it can face the permanent magnet 25 across the partition wall 2d.
In this case, when the throttle opening becomes the first opening slightly opened from the idling opening and the second and third openings opened further than the idling opening, the permanent magnet 25 causes the magnetic sensor 2 to move.
8a to 28c so as to face the sensors 28a to 28c.
The position of is set.

Here, in adjusting the piston valve axial mounting position of the base plate 27, the piston valve 9 is slightly moved from the idling position (for example, 3.5 to 43).
When the first opening is increased, the base plate 27 is swung by the rotation of the eccentric cam 32, and the magnetic sensor 28a at the lower end faces the permanent magnet 25 and reaches the position where an output signal is transmitted. , The bolt 36 is fixed by tightening it. After this adjustment, the eccentric cam 32 is removed, and the sensor chamber 30 is filled with the resin 35.
The eccentric cam 32 does not have to be removed.

The reason why the magnetic sensor 28a at the lower end faces the permanent magnet 25 is adjusted for the following reason. In the state where the opening degree of the piston valve 9 is small, the intake amount largely changes with a slight change in the opening degree of the piston valve 9, whereas it does not change so much when the opening degree increases. Therefore, it is necessary to detect the small opening position of the piston valve 9 with higher accuracy.

In order to further improve the detection position accuracy of the piston valve 9, the permanent magnet 25 and the magnetic sensor 28 are used.
It is desirable to make the change in the magnetic flux density steep with respect to the change in the distance from a to 28c. For that purpose, the permanent magnet 25 is used.
It is advantageous to form a magnetic path consisting of a magnetic plate for concentrating the magnetic flux from the permanent magnet 25 on the magnetic sensors 28a to 28c between the magnetic sensors 28a to 28c.

The lead wires 29 are connected to a throttle opening discriminating circuit (not shown). This discriminating circuit is arranged so that when the magnetic field strength of the permanent magnet 25 due to the axial movement of the piston valve 9 is above a predetermined threshold value, the permanent magnet 25
It is determined that the axial position of the above-mentioned position coincides with any of the magnetic sensors 28a to 28c, and thereby the throttle opening is determined.

Next, the function and effect of this embodiment will be described. According to the opening degree detecting device of the present embodiment, when the piston valve 9 rises from the idling position to the first opened degree slightly, the permanent magnet 25 faces the magnetic sensor 28a at the lower end, and the permanent magnet 25 moves from the magnetic sensor 28a. The output exceeds the predetermined threshold value, so that the throttle opening is determined to be the first opening. When the piston valve 9 further rises to the second and third opening degrees, the permanent magnet 25 sequentially faces the magnetic sensors 28b and 28c, and the magnetic sensor 2
The outputs from 8b and 28c exceed the threshold value, whereby the throttle opening is determined to be the second and third opening.

As described above, in this embodiment, the permanent magnet 25 is fixed to the upper edge of the piston valve 9, and each magnetic sensor 28a is fixed.
Since ~ 28c is fixed to the outer surface of the partition wall 2d of the cylinder portion 2b, the throttle opening of the piston valve 9 can be detected with a simple structure, and it is possible to reduce the size as compared with the case where a conventional rotation mechanism is separately provided. The cost of parts can be reduced.

Further, in this embodiment, the piston valve 9 is
Since the axial position of the piston valve is directly detected, the detection accuracy can be improved as compared with the conventional structure in which the axial movement amount of the piston valve is once converted into the rotation angle and the rotation angle is detected.

Further, according to the present embodiment, since the sensor position adjusting means including the knock pin 31 and the eccentric cam 32 for adjusting the arrangement positions of the magnetic sensors 28a to 28c on the substrate 27 is provided, each magnetic structure is simple. Sensors 28a to 28
error in mounting c on the substrate 27, and the partition wall 2 of the substrate 27
It is possible to absorb the mounting error in d and to raise the mounting position accuracy to the limit. As a result, the detection accuracy can be improved.

Further, in this embodiment, the sensor chamber 30 is formed on the outer surface of the partition wall 2d, and the resin sealing layer 35 is potted inside the sensor chamber 30 to seal the sensor unit 26 with the resin. And deformation can be prevented, and the sealing property can be improved to ensure waterproofing and dustproofing. Moreover, in this embodiment, since the resin sealing layer 35 is formed to be several times thicker than the sensor unit 26, the sealing property of the sensor chamber 30 can be further improved and the lead wire 29 can be used.
The holding power of can be improved.

FIG. 6 is a diagram for explaining an opening degree detecting device according to a modified example of the above embodiment, and FIG.
The same reference numerals as in FIG.

FIG. 6 shows an example in which a cap is attached without resin sealing. That is, the sensor chamber 40 is formed on the outer surface of the partition wall 2d of the cylinder portion 2b, the cap 41 is attached to the opening of the sensor chamber 40 via the gasket 42, and the cap 41 is attached to the boss portion 40b of the sensor chamber 40 by the bolt 44. This is an example of tightening and fixing with. A resin film is coated on the substrate 27 portion of the sensor unit 26, and each lead wire 29 is led out downward from the cutout 40a at the lower edge of the sensor chamber 40 with a seal member 43 interposed. . A communication hole (not shown) communicating with the air vent passage 15 (see FIG. 1) is formed at the bottom of the sensor chamber 40, and the communication hole functions as a breather for adjusting the internal pressure of the sensor chamber 40 to atmospheric pressure. The inside of the sensor chamber 40 is prevented from becoming a negative pressure due to the temperature change, and the intrusion of water due to the negative pressure is prevented.

Also in the above modification, the structure can be simplified, downsized, and the cost can be reduced, and the detection accuracy can be improved because the magnetic sensor mounting position can be adjusted.
The same effect as in the above embodiment can be obtained. Further, since the opening of the sensor chamber 40 is closed by the cap 41, damage due to external force can be avoided, and waterproofing and dustproofing can be achieved. Furthermore, since the cap 41 is simply attached, the curing time for potting the above resin can be eliminated, and the workability and productivity can be improved accordingly.

FIG. 7 and FIG. 8 show still another modification.
This is an example in which the entire sensor case can be swung to adjust the mounting position of the magnetic sensor. The sensor unit 26 is attached to the bottom wall 24a of the sensor case 24 by a magnetic sensor 28a.
˜28c are fixed so as to contact with each other and are resin-sealed by the resin sealing layer 35. The opening of the sensor case 24 may be closed with a cap as described above. A mounting recess 30 for swingably housing the sensor case 24 is formed on the outer surface of the partition wall 2d of the cylinder portion 2b.
The sensor case 24 is fixed to the mounting recess 30 by adjusting the position with bolts 44.

The sensor case 24 has a bottom wall 24a.
Is rotatably supported by a knock pin 31 on the partition wall 2d, and the sensor case 24 is swung by an eccentric cam 32, whereby the arrangement positions of the magnetic sensors 28a to 28c in the piston valve moving direction are adjusted. In this case, the sensor case 24 is fixed to the cab body 2 in advance, the substrate 27 is pivotally supported on the bottom wall 24a of the sensor case 24 by a knock pin, and the substrate 27 is swung by an eccentric cam to set the arrangement position. May be.

In this modification, substantially the same effect as that of the above embodiment can be obtained, and the sensor unit 26 and the sensor case 24 are provided.
Since it is housed inside, the product can be inspected as a single product without being attached to the cab body 2, and can be shared by different carburetors of different models, and further damage during transportation and handling can be prevented.

In the above embodiment, the case of application to the VM type carburetor has been described as an example, but the present invention can also be applied to the SU type carburetor equipped with a rotary butterfly valve.
In this case, a magnet is arranged in the piston valve that automatically moves up and down by the suction negative pressure. Further, in the above embodiment, the cylindrical piston valve is taken as an example, but the present invention can be applied to the plate valve as well.

[0046]

As described above, according to the opening degree detecting device of the carburetor according to the present invention, the magnet is fixed to the variable area valve, and the magnetic sensor is attached to the outer surface of the partition wall at a position where it can face the magnet. With the simple structure, it is possible to reduce the size, reduce the cost, and improve the detection accuracy. Further, since the sensor position adjusting means for changing the sliding direction position of the area variable valve of the magnetic sensor is provided. The effect of absorbing the error of each component is to improve the mounting position accuracy and further improve the detection accuracy.

[Brief description of drawings]

FIG. 1 is a side view for explaining an opening degree detection device for a carburetor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the apparatus of the above embodiment.

FIG. 3 is a cross-sectional view showing a main part of detection of the apparatus of the above embodiment.

FIG. 4 is a schematic view showing a sensor position adjusting means of the apparatus of the above embodiment.

FIG. 5 is a schematic cross-sectional plan view showing a main part of detection of the apparatus according to the embodiment.

FIG. 6 is a sectional view showing a main part of detection according to a modification of the above embodiment.

FIG. 7 is a side view of another modification of the above embodiment.

FIG. 8 is a cross-sectional view of a main part of detection according to another modification.

[Explanation of symbols]

 1 Vaporizer 2 Cab body 2d Partition wall 6 Venturi passage 7 Valve chamber 9 Piston valve (Variable area valve) 25 Permanent magnet 27 Substrate 28a-28c Magnetic sensor 31 Knock pin (Support pin) 32 Eccentric cam

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area F02M 19/00 H G01B 7/30 101 B

Claims (2)

[Claims] 1. A cab body having a venturi passage and a valve chamber formed so as to open to the passage, and an area variable valve slidably arranged in the valve chamber for changing a venturi passage area. In the carburetor opening detection device, a magnet is fixed to the variable area valve, and a magnetic sensor that generates an output according to the strength of the magnetic field from the magnet is used as the magnet on the outer surface of the partition wall that forms the valve chamber. An opening degree detecting device for a carburetor, which is provided at a position where it can face each other, and is provided with a sensor position adjusting means for changing a mounting position of the magnetic sensor in a sliding direction of the variable area valve. 2. The substrate according to claim 1, wherein the sensor position adjusting means separates the substrate on which the magnetic sensor is arranged and fixed from the magnetic sensor in a direction substantially perpendicular to a sliding direction of the area variable valve. A carburetor opening degree detection device, comprising: a support pin that pivotally supports the above-mentioned portion on the partition wall and an eccentric cam that swings the substrate about the support pin as a rotation center.