Relay device and relay device mounting structure
View Patent ↗Terminals ( 11, 13 ) for electrical connection respectively have front end portions ( 11 b, 13 b ) to be joined to a wiring board ( 20 ) with solder and base end portions ( 11 a, 13 a ) drawn outside from a cover ( 7 ) made of heat-expanding material. In order for the base end portions to absorb stress countering the external force received from the cover subjected to thermal expansion due to the heat generated by an electromagnetic coil ( 5 ) by the deflection deformation of the intermediate portions ( 11 c, 13 c ) of the terminals positioned closer to the cover than the wiring board 20 with the relay device mounted on the wiring board, the terminals are formed with a predetermined length of L′ in the extending direction of the terminals so that the length required for necessary flexibility is secured for the intermediate portions.
1. A relay device mounting structure comprising:
a cover made of heat-expanding material for containing a heat generating element;
a wiring board; and
a plurality of terminals, base end portions being defined by one ends of the terminals and projecting from different places of the cover, respectively, and front end portions being defined by the other ends of the terminals and being joined to different places on the wiring board with solder which does not contain Pb, respectively,
wherein the terminals have a length between the base end portions and the front end portions so that stress caused by a displacement between the base end portions due to heat generated by the hear generating element is absorbed at the front end portions by utilizing a predetermined flexibility which the terminals have, and
wherein the length is determined based a sectional area of the terminal.
2. The relay device mounting structure according to claim 1 , further comprising a space adjusting projection, wherein the space adjusting projecting is abutted against the wiring board when the terminals are joined to the wiring board so as to provide the terminals of the length between the cover and the wiring board.
3. The relay device mounting structure according to claim 2 , wherein the space adjusting protection extends from the cover along a terminal extending direction.
4. The relay device mounting structure according to claim 2 , wherein the space adjusting projection is formed at at least one of the terminals.
5. The relay device mounting structure according to claim 4 , wherein the space adjusting projection is formed by changing thickness of the terminal.
6. The relay device mounting structure according to claim 1 , wherein the length is determined based the sectional area and material of the terminal.
7. The relay device mounting structure according to claim 1 , wherein the heat generating element is an electromagnetic coil for switching contact.
8. The relay device mounting structure according to claim 1 further comprising a heat radiating member attached to the terminal between the cover and the wiring board.
9. The relay device mounting structure according to claim 8 , wherein
the heat radiating member is made of simple material whose thermal expansion coefficient is lower than that of the cover, and
the heat radiating member is attached to the terminals by passing the terminals through the heat radiating member.