| 摘要 |
PROBLEM TO BE SOLVED: To seal a part between a boss member and a connecting pin by lubricating oil containing magnetic fluid by providing magnetic seal means between the boss member and the connecting pin. SOLUTION: Respective oil retaining bushes 5 are fitted in a bush fitting hole 1A of an arm boss 1, and a connecting pin 3 is inserted on the inner peripheral sides of respective oil retaining bushes 5. The connecting pin 3 is inserted and fitted into pin insertion holes 2A of respective brackets 2, and the arm boss 1 and respective brackets 2 are rotatably connected to one another. Magnetic lubricating oil 7 is impregnated in respective oil retaining bushes 5, and the magnetic lubricating oil 7 is filled in a lubricating oil reservoir 6. Respective magnetic seal devices 8 and respective dust seals 13 are provided in the bush fitting hole 1A of the arm boss 1 so as to be positioned between the arm boss and the connecting pin 3. Respective magnetic seal devices 8 magnetically trap the magnetic lubricating oil 7 to seal a part between the arm boss 1 and the connecting pin 3 together with the trapped magnetic lubricating oil 7 without being slid to the connecting pin 3. |
