Needle attaching structure of rotating shaft and meter device
View Patent ↗When a press-in part 81 is inserted into a press-in hole 93 , a vertex of the press-in part 81 deformed to a form along the inner surface of the press-in hole 93 comes into contact with the inner surface of the press-in hole 93 and a press-in force when the press-in part 81 is inserted into the press-in hole 93 or a pull-out force when the press-in part 81 is pulled out from the press-in hole 93 is set in according with the length of an intersecting line that a surface on which the outer surface of the press-in part 81 comes into contact with the inner surface of the press-in hole 93 and a section intersecting orthogonally to the axial direction of the press-in part 81 intersect.
1. A meter device comprising:
a rotating shaft that has an end part protruding to a front surface of the meter device and rotates by a turning force transmitted from a motor through a gear;
a needle that has in a lower surface a press-in hole to which a press-in part in the end part of the rotating shaft is pressed-in and rotates along the front surface; and
a light source that is provided in a bottom of the meter device and outputs an illuminating light advancing in the rotating shaft from a base end part to the end part to emit the light from the needle,
wherein the rotating shaft having light guide characteristics is pressed-in to the press-in hole of the needle, the press-in hole has a true circular form in section,
the press-in part in the end part of the rotating shaft has a regular n polygonal form in section, such that the press-in part has n angular parts, wherein 5≤n,
when the press-in part is inserted into the press-in hole, a vertex of the press-in part is deformed to a form along an inner surface of the press-in hole and the vertex comes into contact with the inner surface of the press-in hole,
a press-in force when the press-in part is inserted into the press-in hole or a pull-out force when the press-in part is pulled out from the press-in hole is set in according with a length of an intersecting line that a surface on which an outer surface of the press-in part comes into contact with the inner surface of the press-in hole and a section intersecting orthogonally to an axial direction of the press-in part intersect,
the rotating shaft has an outside diameter gradually increased toward a lower end part thereof, an output gear integrally formed with the rotating shaft at a part of the rotating shaft having the increased outside diameter; and
the rotating shaft is configured to transmit light by the light guide characteristics,
wherein the rotating shaft and the output gear are made out of a resin material to avoid damping the light guide characteristics.
2. The meter device according to claim 1 , wherein the length of the intersecting line is set in accordance with at least one of the diameter of the inner surface of the press-in hole, a length from an axis to the vertex of the press-in part and the number n of the vertices of the press-in part.
3. The meter device according to claim 1 , wherein as a result of an axis of the rotating shaft and an axis of the press-in hole being arranged on a same straight line, the vertex of the press-in part is located outside the inner surface of the press-in hole.