There are those who insist that 'homework' is the answer to the high stakes game of testing that politicians have gotten us into. What people who don't know child development fail to understand is that children need to learn how to be part of the family and how to be children before they become too old.
Elementary children are already in school for 6 1/2 hours a day, five days a week. Add the hours that mom, dad, and/or guardians must use to earn a living and keep up a home, and the amount of hours that a child can participate as a family member and be an actual child gets cut down to a bare minimum.
I'm a minimalist when it comes to giving out homework. I try to make homework simple, but meaningful, and something that does not take up too much of the family's time or create 'power struggles' at home.
You didn't indicate what the '1 hour' of homework is comprised of for your son. If some of that time is supposed to be reading homework, nothing is more pleasurable than reading a good book with your parent. Pick one that you enjoyed as a kid. One of my sons got to read the Tom Swift, Jr. books with me, and I'm attempting to pass on to grandchildren my wonderful My Book House that my mother read when she was a child, and I grew up on too.
There are some great online reading resources. Some are subscription based and some are free. My favorites are Raz-Kids (which I have gotten access for my students through a school subscription) and We Give Books, which is free (It also can inspire children to read because the more they read online the more books get donated to worthy causes.)
If you son is self-motivated, either ask the teacher if he could switch some of the more mundane homework assignments for original research projects that he could do at home using the Internet. Even if the teacher isn't open to this substitution, sometimes children thrive being encouraged to ask their own questions and follow their own 'wonderings'.
The key to getting children to 'do' homework is to avoid power struggles. The more you can turn it around by making it pleasurable and meaningful, the more likely he'll become a life-long learner on his own.