求翻译：为实现上述目的，本发明采取的技术方案为：一种紧凑型灵敏气缸，包括有气缸后盖（1）、气缸前盖（9）分别与缸筒（13）连接，缸筒（13）上设有上通气口（15）活塞杆（8）上设有活塞（5），其主要特点是包括有在气缸后盖（1）上设有与主气缸连接用螺纹孔（2）。是什么意思？

For implementation above purpose, this invention take of technology programme for: a compact type sensitive cylinder, including has cylinder Hou cover (1), and cylinder Qian cover (9) respectively and cylinder tube (13) connection, cylinder tube (13) Shang has Shang ventilation mouth (15) piston rod (8) Shang has piston (5), its main features is including has in cylinder Hou cover (1) Shang has and main cylinder connection with thread hole (2).