Work vehicle periphery monitoring system and work vehicle periphery monitoring method

1. A work vehicle periphery monitoring system comprising:

an alarm range storage unit that stores a predetermined alarm range, in which an alarm output is required when an object is present, in a detection range of an object detection device that detects an object present in a periphery of a work vehicle;

a work mode determination unit that determines a work mode of the work vehicle;

an alarm range changing unit that changes the alarm range in the detection range when it is determined that the work mode is a specific work mode; and

an alarm control unit that causes an alarm device to output an alarm when an object is present in the alarm range,

wherein the work mode determination unit determines that the work mode of the work vehicle is the specific work mode in a case where a gear stage of a transmission included in the work vehicle is a low gear stage, on a basis of operation data of a transmission operation device that operates the transmission.

2. The work vehicle periphery monitoring system according to claim 1 , wherein

the predetermined alarm range is an alarm range defined behind a predetermined portion of the work vehicle.

3. A The work vehicle periphery monitoring system according to claim 1 , wherein the work vehicle is an articulated type work vehicle; and wherein the gear stage of the transmission included in the articulated type work vehicle is a rearward low gear stage.

4. The work vehicle periphery monitoring system according to claim 1 , wherein

the alarm range changing unit changes the alarm range so that a dimension in a vehicle width direction of the work vehicle decreases.