JPH0375737B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for assembling a throttle sensor for detecting the throttle valve opening of an internal combustion engine.

2. Description of the Related Art Detection of the opening degree of a throttle valve in an internal combustion engine is generally performed using a throttle sensor consisting of a potentiometer that outputs an output according to the rotation angle of a throttle shaft. This throttle valve opening signal is used to detect acceleration and deceleration of the internal combustion engine, but in recent years, attempts have been made to detect the engine intake air amount from the throttle valve opening. Very high detection accuracy is required for the throttle sensor.

4 and 5 show an example of the configuration of a throttle chamber 2 equipped with a throttle sensor 1. FIG.

The throttle shaft 3 is disposed across the intake passage 4 of the throttle chamber 2, and
A disk-shaped valve body 5 is attached to the center thereof, and both ends thereof are rotatably supported by the throttle chamber 2 via ball bearings 6, respectively. A return spring 7 is attached to one end of the throttle shaft 3, and a throttle sensor 1 is disposed at the opposite end.

The throttle sensor 1 is of the potentiometer type and is roughly composed of a brush 8 attached to the end of the throttle shaft 3 and a sensor case 9 attached to the outer surface of the throttle chamber 2. ing. As shown in FIG. 6, the sensor case 9 includes an arc-shaped sliding resistor 1.
A ceramic substrate 16 on which 0 is printed is fixed, and a positioning recess 11 is formed at the center of the arc of the sliding resistor 10 to fit with the tip of the throttle shaft 3. Furthermore, four mounting holes 13 are formed through the periphery of the sensor case 9 for fixing the sensor case 9 to the throttle chamber 2 with screws 12. are elongated holes along an arc centered on the positioning recess 11. In this example, two tracks of the sliding resistor 10 are provided, and an arcuate conductor 14 is printed adjacent to these tracks. Then, the brush 8 has four brushes corresponding to the patterns of the sliding resistor 10 and the conductor 14.
This brush holder 15 is provided and is held via a brush holder 15 press-fitted into the throttle shaft 3.

That is, in the throttle sensor 1, in order to make the output characteristics of each product uniform, the sensor case 9 is fixed so that the output when the throttle valve is fully closed is a reference value (for example, 0.5V). The position is finely adjusted in the direction of arrow A or B in FIG. 6, and the screw 12 is firmly tightened and fixed at the appropriate position where the output becomes the reference value. At that time, if the rotation locus of the brush 8 and the arc of the sliding resistor 10 do not match correctly, normal output characteristics cannot be obtained, so the positioning recess 11 must be fitted to the tip of the throttle shaft 3. Therefore, the center of the arc of the sliding resistor 10 and the center of the throttle shaft 3 are centered at a concentric position.

Problems to be Solved by the Invention As mentioned above, since the positioning recess 11 of the sensor case 9 is for centering with respect to the throttle shaft 3, the fitting clearance with the tip of the throttle shaft 3 is set to be quite small. There is a need to. In this case, when the sensor case 9 is finally fixed after output adjustment, it is almost impossible to keep the inner circumferential surface of the positioning recess 11 and the outer circumferential surface of the throttle shaft 3 in a non-contact state. In this case, the throttle shaft 3 comes into contact with a part of the inner peripheral surface of the positioning recess 11.

Therefore, the rotation of the throttle shaft 3 may not be smooth, and in extreme cases, there is a possibility that the throttle shaft 3 may not return smoothly to the closing direction. Further, there were problems such as momentary interruption of sensor output due to abrasion powder generated at the contact portion.

Means for Solving the Problems Accordingly, the present invention provides a method for assembling a throttle sensor in which the throttle shaft and the sensor case can be maintained in a non-contact state. That is, in the present invention, a brush is attached to the end of the throttle shaft protruding from the throttle chamber, and a sensor case having an arc-shaped sliding resistor is fixed to the throttle chamber, and the sensor case In the throttle sensor assembly method in which the output characteristics are adjusted by finely adjusting the fixing position of the Using a jig that fits into the through hole, adjust the fixing position of the sensor case while keeping the through hole and the end of the throttle shaft in a concentric position, and then close the through hole with a cover. It is characterized by

Function: First, a brush is attached to the end of the throttle shaft protruding from the throttle chamber, and a sensor case is placed so as to cover it. Then, a jig is inserted into the through hole, and the through hole and the end of the throttle shaft are maintained in a concentric position via this jig. In this state, the position of the sensor case is finely adjusted in the rotational direction so that, for example, the output when the throttle valve is fully closed becomes the reference value, and the sensor case is firmly fixed at an appropriate position. Finally, the through hole is closed using a cover.

Embodiment FIG. 1 is an explanatory diagram showing an embodiment of the present invention. Note that the basic configurations of the throttle sensor 1 and the throttle chamber 2 are not particularly different from those of the conventional ones, so a description thereof will be omitted.

The sensor case 9 used in this assembly method is provided with a through hole 21 in place of the positioning recess 11 described above. This through hole 21 is located at the center of the arc of the sliding resistor 10 on the ceramic substrate 16, and has a large diameter portion 21a on the outside of the sensor case 9, and a small diameter portion 21b on the inside. have. The small diameter portion 21b is set to be slightly larger than the diameter of the tip of the throttle shaft 3.

The assembly method of this embodiment will be explained according to the working procedure. First, a brush holder 15 equipped with a brush 8 is press-fitted and fixed to the end of the throttle shaft 3 protruding from the throttle chamber 2. The throttle shaft 3 is supported by the throttle chamber 2 via a pair of ball bearings 6, as described above.

Next, attach the sensor case 9 to the throttle chamber 2.
Temporarily fasten with screws 12. Then, a jig 22 is inserted into the through hole 21 and centered with the tip of the throttle shaft 3. The jig 22
In this case, the outer peripheral surface 22a is the large diameter portion 21 of the through hole 21.
It has a cylindrical shape that fits relatively tightly into the throttle shaft 3, and has a recess 22b in the center of the tip that fits into the tip of the throttle shaft 3. Therefore, if the sensor case 9 is positioned via this jig 22,
The through hole 21 and the throttle shaft 3 are maintained in a concentric position, and as a result, the rotation locus of the brush 8 and the arc of the sliding resistor 10 correctly match.

Next, with this jig 22 inserted, finely adjust the position of the sensor case 9 in the rotational direction so that the output when the throttle valve is fully closed is the reference value, and firmly tighten the screw 12 at the appropriate position. to fix the sensor case 9.

Next, the large diameter portion 21a of the through hole 21
A disk-shaped cover 23 made of synthetic resin or the like is fitted onto the cover 23, and the periphery is attached with an adhesive 24 to seal the cover 23 to maintain airtightness. Alternatively, heat welding may be performed without using the adhesive 24.

In the embodiment shown in FIG. 3, the through hole 25 of the sensor case 9 is a simple cylindrical hole, and a cover 26 made of rubber is fitted therein by utilizing its elasticity. According to this embodiment, since the cover 26 itself maintains airtightness, processes such as adhesion are not required.

Effects of the Invention As is clear from the above explanation, according to the method for assembling a throttle sensor according to the present invention, the center of the arc of the sliding resistor and the throttle shaft are centered using a jig, so that the throttle It is possible to reliably maintain the torque shaft in a non-contact state with respect to the sensor case. Therefore, it is possible to prevent the throttle shaft from malfunctioning, and also to prevent the generation of abrasion powder that can cause various malfunctions.

In addition, since the sensor case is positioned by direct contact with the jig, the center of the arc of the sliding resistor and the throttle shaft can be centered with higher precision than with conventional methods. Therefore, the desired output characteristics can be reliably obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the assembly method according to the present invention, Fig. 2 is a sectional view showing a state in which a cover is attached to a through hole, and Fig. 3 is an explanatory diagram showing an embodiment in which a cover made of rubber is attached. 4 is a sectional view of a throttle chamber equipped with a conventional throttle sensor, FIG. 5 is a sectional view taken along the line - in FIG. 4, and FIG. 6 is a sectional view of a conventional throttle chamber. FIG. 3...Throttle shaft, 9...Sensor case, 16...Ceramic board, 21...Through hole,
22...Jig, 23...Cover.

Claims (1)

[Claims] 1 Attach a brush to the end of the throttle shaft protruding from the throttle chamber, and
In a method for assembling a throttle sensor, in which a sensor case having an arcuate sliding resistor is fixed to the throttle chamber, and output characteristics are adjusted by finely adjusting the fixing position of the sensor case. A through hole is previously provided in the sensor case at the center of the arc of the sliding resistor, and a jig that fits into the through hole is used to align the through hole and the end of the throttle shaft in a concentric position. A method for assembling a throttle sensor, characterized in that the fixing position of the sensor case is adjusted while maintaining the position, and then the through hole is closed with a cover.