Bill Cosby -- Alerts Playboy Mansion ... I Need Ammo Against Accuser

Bill Cosby and his attorneys are turning the Playboy Mansion upside down ... and hitting up Hugh Hefner for anything to help take down Cosby's latest sexual assault accuser.

TMZ broke the story ... Chloe Goins filed criminal charges against Cosby for an alleged 2008 incident at the Mansion ... where she claims Cosby was masturbating and sucking her toes.

Sources inside the Mansion tell TMZ ... Cosby's team reacted immediately -- asking if Hef's security team has any surveillance footage from the night of the party. We're told they also want names of employees and other guests who might be able to recall seeing Cosby and Goins.

And there's this -- in what seems like a preemptive move ... Cosby's attorneys are asking Hef if he's aware of any other Playboy models planning to come forward with similar allegations.

As we told you ... Goins may have waited too long to go to cops -- the statute of limitations may have run -- but team Cos is prepping for the worst case scenario.