Throttle valve device and method for manufacturing the same

1. A throttle valve device comprising:

a body having a passage and a motor space;

a valve arranged in the passage of the body and configured to rotate together with a shaft to open and close the passage;

a motor held in the motor space of the body and configured to operate according to an electric signal and rotate the shaft via rotation of a valve gear such that the shaft is located at a valve fully-closed position at which the valve is fully closed, a valve fully-open position at which the valve is fully open, or a valve intermediate position which is between the valve fully-closed position and the valve fully-open position;

a coil spring arranged around an outer circumference of the shaft in the body and located between the valve gear and the valve, the coil spring having a first spring end extending outward in a radial direction of the coil spring at an end of the coil spring, and a second spring end extending outward in the radial direction at another end of the coil spring, the coil spring being configured to generate a spring force as an opposing force at a time of transmission of rotation from the motor to the shaft;

a first guide having a first through hole through which the shaft extends at a central position of the first guide, a first end surface of the coil spring facing the first guide, the first guide being configured to rotate around the shaft together with the first spring end;

a second guide having a second through hole through which the shaft extends at a central position of the second guide, a second end surface of the coil spring facing the second guide, the second guide being configured to rotate around the shaft together with the second spring end;

a driving portion configured to be rotated together with the valve gear, the driving portion being in contact with the first spring end and the second spring end at the valve intermediate position of the shaft, the driving portion pushing the first spring end or the second spring end against the opposing force of the coil spring during a first movement of the shaft or a second movement of the shaft, the first movement being movement of the shaft from the valve intermediate position to the valve fully-closed position, the second movement being movement of the shaft from the valve intermediate position to the valve fully-open position; and

a holding portion provided in the body, the holding portion being in contact with the first spring end and the second spring end at the valve intermediate position of the shaft, the holding portion holding the first spring end or the second spring end during the first movement or the second movement of the shaft, wherein

the first guide includes a first insertion hole, and the second guide includes a second insertion hole, and

an axis of the first insertion hole in an axial direction of the shaft and an axis of the second insertion hole in the axial direction are located at the same position when both the first spring end and the second spring end are positioned near the valve intermediate position of the shaft and are not in contact with the holding portion.

2. A method for manufacturing the throttle valve device according to claim 1 , comprising:

using a first jig, the first jig including

a first holding shaft that can be inserted into the first through hole of the first guide and the second through hole of the second guide,

a jig pin that can be inserted into the first insertion hole of the first guide and the second insertion hole of the second guide, and

a first base portion that houses the first holding shaft to be movable in the axial direction and fixes the jig pin;

using a second jig, the second jig including

a second holding shaft that can be inserted into the second through hole of the second guide, and

a second base portion that houses the second holding shaft to be movable in the axial direction;

supporting the second guide with the second jig by inserting the second holding shaft into the second through hole;

supporting the first guide, the coil spring and the second guide with the first jig and the second jig without a load on the coil spring, wherein the supporting without the load includes placing the coil spring between the second guide and the first guide, inserting the first holding shaft into the first through hole, and inserting the jig pin into the first insertion hole;

supporting the first guide, the coil spring and the second guide with the first jig under a load on the coil spring, wherein the supporting under the load includes rotating the first jig around the first holding shaft to cause the jig pin to face the second insertion hole, and compressing the coil spring to insert the jig pin into the second insertion hole and insert the first holding shaft into the second through hole;

removing the second jig from the first guide, the coil spring and the second guide in a state where the first jig supports the first guide, the coil spring and the second guide;

attaching the first guide, the coil spring and the second guide to the body by the first jig such that the first spring end and the second spring end face the holding portion without contacting the holding portion; and

removing the first jig from the first guide, the coil spring and the second guide such that the first spring end and the second spring end come into contact with the holding portion by the spring force of the coil spring.

3. The method for manufacturing the throttle valve device, according to claim 2 , wherein

at least one of the first insertion hole of the first guide or the second insertion hole of the second guide is an elongated hole extending in a circumferential direction centered on the shaft.

4. The method for manufacturing the throttle valve device, according to claim 2 , wherein

the first guide includes a first spring hole through which the first spring end of the coil spring extends,

the second guide includes a second spring hole through which the second spring end of the coil spring extends, and

the supporting without the load on the coil spring includes inserting the first spring end into the first spring hole, and inserting the second spring end into the second spring hole.

5. The method for manufacturing the throttle valve device, according to claim 2 , wherein

an end of the shaft facing the valve gear has an engaging portion, and

the second holding shaft includes a second holding-shaft engaging portion that is the same in shape as the engaging portion, and

the supporting without the load on the coil spring includes arranging the second holding-shaft engaging portion to be engaged with the first holding shaft of the first jig such that the second holding shaft is coaxial with the first holding shaft.

6. The throttle valve device according to claim 1 , wherein

at least one of the first insertion hole of the first guide or the second insertion hole of the second guide is an elongated hole extending in a circumferential direction centered on the shaft.

7. The throttle valve device according to claim 1 , wherein

the first guide includes a first spring hole through which the first spring end of the coil spring extends, and

the second guide includes a second spring hole through which the second spring end of the coil spring extends.

8. The throttle valve device according to claim 1 , wherein

an end of the shaft facing the valve gear has an engaging portion, and

the engaging portion engages with the valve gear such that the shaft is rotatable together with the valve gear.