Here's how an active engine mount works:


This front engine mount was cut apart from a 1999 ES300:


Here's a section view, where you can see the top part that bolts to the engine is a separate rubber bushing. The outside frame and main body is below.

Here's what it looks like underneath the bottom diaphragm.

Here's the diaphragm that separates the vacuum from the hydraulic fluid.

Here's a closer look at that top piece. It's just a nub that sits on top.