PURPOSE: To allow a cushion rubber to move integratedly without making a space with a rubber screen and to make the cushion rubber function as a cushioning material between a rubber screen and a subframe by forming a space for inserting the subframe in the lower part and a neck-in part in the upper part.

CONSTITUTION: A subframe cushion rubber 3a has a slot-shaped space for inserting a subframe 2 in the lower part and a neck-in part in the upper part. The insertion of the cushion rubber 3a between a rubber screen 1 and the subframe 2 makes the neck-in part act as a spring and move integratedly following up well the vibration of the rubber screen 1. With close contact kept between the cushion rubber 3a and the rubber screen 1 both horizontally and vertically, there arises no gap between them. Since there is no frictional movement between them, the abrasion of the rubber screen can be reduced.