Hi Marie, 

Typically, pears do not bloom/bear fruit for the first few years. This is most likely the key issue here!! But, I have some other considerations for pollination and encouraging bloom. 

Pears will set up floral buds the previous growing season. These buds then overwinter and bloom the following spring. If trees are stressed out, they will not put energy into making flowers for the next season. Giving pears enough water throughout the season and providing proper fertilization is key to helping them bloom. 

If you are pruning the pear tree in the winter, make sure that you are leaving enough buds to bloom, too. 

My next concern is pollination. I'm glad you're growing different types of fruit! However, pears will only be pollinated by other pears. They can be picky about which pears cross-pollinate too. Here is information on pear cross-pollination: https://treefruit.wsu.edu/web-article/pear-pollination/. 

Best,