Patent ID: 9139983
Filing Date: 2015-09-22
Classification: E02F

Abstract:
1. A construction machine comprising: an automotive vehicle body; an engine mounted on said vehicle body; a control device which electronically controls said engine; a hydraulic pump which is provided with a displacement control mechanism to variably control delivery displacement of said hydraulic pump, and which is driven by said engine to deliver a pressurized oil; a hydraulic motor for traveling of the vehicle body and which is driven by the pressurized oil delivered from said hydraulic pump; a traveling operation device provided on said vehicle body, to drive and operate said hydraulic motor during traveling; and a traveling speed switching member-which is provided on said vehicle body and switches a traveling speed of said hydraulic motor between at least two stages of a low speed and a high speed, wherein said control device includes: an output lowering determination unit for determining whether or not a fuel injection amount to be supplied to said engine is limited and an engine output is in a lowered state; and a low-speed control unit in which, when it is determined by said output lowering determination unit that said engine output is in the lowered state, control is executed to set a predetermined low speed state having a speed lower than said high speed by an operation of said traveling operation device even if said traveling speed switching member has been switched to said high speed, wherein said low-speed control unit has a small displacement holding unit to hold the delivery displacement of said hydraulic plump in a small displacement state by said displacement control mechanism, when it is determined by said output lowering determination unit that an output of said engine is in the lowered state for keeping said traveling speed at the speed of said predetermined low speed state.