维护和恢复所需状态以及确定和评估实际状况的所有措施的总称。它包括服务，检查和维修。维护工作可以由操作员本人承担，也可以作为服务购买。通常，此服务由制造商自己或授权的客户服务承担。

          Collective term for all measures for maintaining and restoring the desired state as well as for determining and evaluation the actual condition. It comprises service, inspection, and repair. Maintenance works can be undertaken by the operator himself or as bought as a service. Usually this service is covered by the manufacturer's own or authorised customer service.