Remember that Eastern war fighting isn't the same as Western. You want to become the dominate power in the Pacific. The USA is the only other rival in the ocean. You know you cannot win a protracted war. You know that the USA would probably be fighting soon in Europe (even the US strategey was "Germany first"). A fast, quick strike, disabling it's naval power would force a peace with the USA. Remember, Eastern...war and politics occur at the same time. Just like Korea and peace talks, or Vietnam and peace talks. They happen at the same time. Not one excluding the other. It's not a "We'll go in and take over, then shift to peacetime" like we do.
They expected the US to see that there was no way to effectively fight for dominance in the Pacific without a fleet, so the US would sue for peace and proceed about it's merry way with Europe. By the time the US got around to Japan, the Japanese would have the Pacific rim pretty much sewed up and the Asian masses would be flocking to the Japanese to throw off the yoke of white imperialism.
There simply was never any reason, nor plan to invade the USA. They just miscalculated what was going to happen. They didn't get the carriers, they didn't get the oil tank farm on Ford Island. They didn't plan on how pissed off the Americans would get. They didn't plan on us reading their mail. The war was lost for Japan (as it probably was for Germany) in 1942. All that remained to do was the killing and dying for the next few years until the world lined up for the next conflict.
In the end, the Japanese still achieved the national goal of being the primary power in the Pacific. They just did it economically, with our backing. From an Eastern point of view, they actually won WWII because their national aims were achieved (though not as grand a scale).
Ross