Throttle Valve Opening Sensor

The present invention relates to a throttle valve opening sensor for use with an internal combustion engine.

A conventional throttle valve opening sensor includes a substrate provided with a throttle valve opening detecting portion, a rotor adapted to be rotated in association with rotation of a throttle valve, a housing for rotatably supporting the rotor and incorporating the substrate, a packing mounted in the housing for sealing the substrate, and a contact mounted on the rotor and adapted to slide on the opening detecting portion. Air tightness of a substrate sealing part of the sensor is obtainable by using a resin filler or applying an adhesive material to the substrate fixed to the housing with a rubber packing or the like.

However, in the conventional throttle valve opening sensor, the air tightness of the substrate sealing part is deteriorated by temperature change and vibration as time is elapsed. Furthermore, workability is reduced, thereby increasing the manufacturing steps and costs.

It is a primary object of the present invention to provide a throttle valve opening sensor which may reliably maintain the air tightness of the substrate sealing part for a long time against temperature change and vibration.

It is another object of the present invention to provide a throttle valve opening sensor which may improve workability and reduce costs.

According to the present invention, in a throttle valve opening sensor including a substrate provided with a throttle valve opening detecting portion, a rotor adapted to be rotated in association with rotation of a throttle valve, a housing for rotatably supporting the rotor and incorporating the substrate, a packing mounted in the housing for sealing the substrate, and a contact mounted on the rotor and adapted to slide on the opening detecting portion; the improvement comprises a substrate pressing portion formed at the packing for inwardly pressing the substrate, an O-ring projecting portion formed at the packing on the outer peripheral side of the substrate pressing portion and tightly contacting with the housing, and a cover provided outside the packing for inwardly pressing the substrate pressing portion and the projecting portion of the packing.

With this arrangement, the packing is inwardly pressed by the cover, and accordingly, the O-ring projecting portion of the packing is pressed against the housing to thereby secure the air tightness. Furthermore, an inner part of the packing is pressed by the cover against the substrate to thereby secure a pressing effect of the packing against the substrate.

The invention will be more fully understood from the following detailed description and appended claims when taken with the drawings.

FIG. 1 is a vertical sectional view of a preferred embodiment according to the present invention;

FIG. 2 is a plan view in partly section of a part in FIG. 1; and

FIG. 3 is an enlarged view of a part A shown in FIG. 1.

Referring to FIGS. 1 to 3, reference numeral 3 designates a housing for incorporating a substrate 1, a rotor 2 and an external connecting lever 4. The housing 3 is formed with a bearing portion for rotatably supporting a shaft 5 of the rotor 2. The rotor 2 is provided with first and second contacts 9 and 10 each having a pair of contact portions. The substrate 1 is positioned in the housing 3 so that the contacts 9 and 10 may come into contact therewith.

Terminals 11 and 14 connected with power supply lead wires are connected to the substrate 1. Similarly, terminals 12 and 13 connected with signal output lead wires are connected to the substrate 1.

The shaft 5 of the rotor 2 is mounted on the bearing portion of the housing 3. a return spring (torsion spring) 6 is provided between the housing 3 and the external connecting lever 4 in such a manner that one end of the spring 6 is fixed to the lever 4, and the other end is fixed to the housing 3, thereby resiliently restricting the rotation of the lever 4. The external connecting lever 4 is connected to the shaft 5 of the rotor 2.

The rotor 2 is rotated in association with rotation of a throttle valve (not shown), and as a result, the first and second contacts 9 and 10 fixed to the rotor 2 are slid on the upper surfaces of a throttle valve opening detecting portion 15 and an idling position detecting portion 16 both printed on the substrate 1.

As shown in FIG. 2, the throttle valve opening detecting portion 15 printed on the substrate 1 has a form of partial sector about the center of the shaft 5 of the rotor 2. The idling position detecting portion 16 printed on the substrate 1 is opposed to the opening detecting portion 15, and has a form of partial sector about the center of the shaft 5. The opening detecting portion 15 consists of a resistor 15a and a collector 15b, while the idling position detecting portion 16 consists of a conductor 16a and a collector 16b.

As shown in FIG. 3, a rubber packing 7 is provided outside the substrate 1. The rubber packing 7 is formed at its outer periphery with an O-ring projecting portion 7a for sealing a seal portion 3a of the housing 3, and is further formed with a substrate pressing portion 7c for inwardly pressing the substrate 1 with a groove 7b defined therebetween. A cover 8 is provided outside the rubber packing 7, and is fixed by a caulking portion 3b of the housing 3. The cover 8 is formed with an outer pressing portion 8a for inwardly pressing the projecting portion 7a of the rubber packing 7, and with an inner pressing portion 8b for inwardly pressing the rubber packing 7.

With this arrangement, the rubber packing 7 is inwardly pressed by the cover 8, and accordingly, the O-ring projecting portion 7a of the packing 7 is pressed by the outer pressing portion 8a of the cover 8, thus securing the air tightness between the projecting portion 7a of the rubber packing 7 and the seal portion 3a of the housing 3. Furthermore, as the packing 7 is pressed by the inner pressing portion 8b of the cover 8, the substrate 1 is pressed by the substrate pressing portion 7c of the packing 7, thus securing a pressing effect of the packing 7 against the substrate 1.

Having thus described the preferred embodiment of the invention, it should be understood that numerous structural modifications and adaptations may be made without departing from the spirit of the invention.