Routledge, 26, has returned to the club he left in January last year, when he signed for the Magpies, and is expected to play a major role in the push for promotion to the Barclays Premier League.
Routledge has made 36 appearances to date for Newcastle, but has played a peripheral role in recent weeks.
"I think Wayne just needs an arm around him," said QPR boss Neil Warnock. "He is a super lad and a super player."
Thirty-one-year-old Frenchman Chimbonda was released by Blackburn this week and Warnock moved swiftly to add him to the Loftus Road ranks, on a contract running for the rest of the campaign.
Chimbonda told www.qpr.co.uk: "This is a good opportunity for me to be re-born as a footballer. Neil Warnock has given me a chance here and hopefully I can help QPR win promotion to the Premier League.
"I had a good talk with the manager, and he told me he wants me to come here and give my best. He is a manager who likes to win, and I am the same."
Source: PA
Source: PA