SQL Database Transations logs grow rapidly

Hello,

Brief description of my environment:

- ZENworks 10.3.1 (ZCM Standard + ZCM Patch Management)
- 3000 devices managed
- 5 Primary Servers on Windows 2008 Server
- 1 Database Dedicated Server, MS-SQL 2005
- 8 remotes Satellites
- Database size aprox. 7 Gb

My environment has been running normally but the last friday, the transations logs of the database grows aprox. 45gb. and I run out of disk space.

I'm doing daily backups of the database and clean up of the transations logs, but in few hours the logs grows and I run out of disk space.

I don't know what is happening (no updates of ZCM or Operating System), can anyone tell me what I can look ?? I don't know where to begin

Thanks in advanced,