Seat belt retractor and seat belt apparatus

1. A seat belt retractor comprising:

at least one frame comprising a back board and side walls extending from side rims of the back board;

a spool supported by the at least one frame configured to wind up a seat belt;

a motor configured to rotate the spool; and

an electronic control unit mounted to the frame for controlling the driving of the motor, the electronic control unit comprising:

a base;

an electronic control unit board fixed to the base; and

a cover attached to the base to cover the electronic control unit board,

wherein a rim having left and right side rims is formed between opposing surfaces of the base and the attached cover and runs along a periphery of the base,

wherein the rim of the electronic control unit comprises an opening at a lower end that opens an interior of the electronic control unit to an exterior, and

wherein the base comprises a guide wall for guiding liquid that has entered the electronic control unit to the left and right side rims of the base and dropping the liquid through the opening.

2. The seat belt retractor as claimed in claim 1 , wherein the electronic control unit board comprises a connector at the lower end that is electrically connected to the electronic control unit board and can be connected to at least one of a connector of the motor or a vehicle connector to be connected to a vehicle-side electronic component.

3. The seat belt retractor as claimed in claim 2 , wherein the rim of the electronic unit comprises a lower rim, wherein the opening is formed in the lower rim, and wherein the connector at the lower end has terminals that protrude through the opening.

4. The seat belt retractor as claimed in claim 1 , wherein the rim of the electronic unit is formed on the base.

5. The seat belt retractor as claimed in claim 1 , wherein the rim of the electronic control unit comprises a lower rim, and wherein the opening is formed in the lower rim.

6. A seat belt unit comprising:

a seat belt retractor including at least one frame having a back board and side walls extending from side rims of the back board;

wherein the retractor further includes a spool supported by the at least one frame configured to wind up a seat belt, a motor configured to rotate the spool in order to perform at least one of retraction and withdrawal of a seat belt, and an electronic control unit mounted to the frame for controlling the driving of the motor; wherein the electronic control unit includes a base, an electronic control unit board fixed to the base, and a cover attached to the base to cover the electronic control unit board; wherein a rim having left and right side rims is formed between opposing surfaces of the base and the attached cover and runs along a periphery of the base; and wherein the rim of the electronic control unit comprises an opening at a lower end that opens an interior of the electronic control unit to an exterior;

a tongue slidably supported by the seat belt; and

a buckle detachably engaged with the tongue,

wherein the seat belt restrains the occupant by engagement of the tongue and the buckle, and

wherein the base comprises a guide wall for guiding liquid that has entered the electronic control unit to the left and right side rims of the base and dropping the liquid through the opening.

7. The seat belt unit as claimed in claim 6 , wherein the rim of the electronic unit is formed on the base.

8. The seat belt unit as claimed in claim 6 , wherein the rim of the electronic control unit comprises a lower rim, and wherein the opening is formed in the lower rim.

9. The seat belt unit as claimed in claim 6 , wherein the electronic control unit board comprises a connector at the lower end that is electrically connected to the electronic control unit board, wherein the rim of the electronic unit comprises a lower rim in which the opening is formed in the lower rim, and wherein the connector at the lower end has terminals that protrude through the opening.