Actually most Pear trees do not began to produce fruit until they are between 4 and 6 years of age.
Your tree may be still be immature.
Fruit production can also be effected by overall health of the tree, fertilization methods ( over fertilizing will effect fruit and fruit size), chill hours, and poor pollination.
You only mention 1 tree and Pear Trees do need another tree for pollination.
You can find information about compatible trees from you local County Extension Office.
Here are some links with more information.