Throttle valve device and method for magnetizing the same

A method for magnetizing a throttle valve device, the throttle valve device including:

• a body that defines a passage, a motor space, and a connecting portion that connects the motor space to the passage;
• a valve that is disposed in the passage and is configured to control a flow rate by adjusting a passage area of the passage;
• a motor that is disposed in the motor space and is configured to generate a driving force for the valve to rotate;
• and
• a cover that covers an open end of the body, wherein
• the motor includes:
• a motor yoke made of a magnetic material;
• a magnet that is arranged on an inner circumferential surface of the motor yoke;
• a motor shaft that is disposed inside the motor yoke;
• a pair of motor bearings that rotatably support the motor shaft;
• an armature core that is coupled to the motor shaft in the motor yoke;
• a commutator that is coupled to the motor shaft in the motor yoke;
• a brush that is configured to energize the commutator;
• and
• a brush holder that holds the brush,
• the method comprising:
• a magnet arranging step of arranging the motor yoke in the motor space of the body and arranging the magnet in the motor yoke;
• and
• a magnetizing step of magnetizing the magnet disposed in the motor space of the body.

The method according to clam 4, wherein

• the magnet arranging step further includes:
• bringing one ends of a pair of magnets into contact with a holding portion formed in the inner circumferential surface of the motor yoke;
• providing a holding spring in a space between the other ends of the pair of magnets;
• and
• biasing the pair of magnets against the holding portion by the holding spring.