Work vehicle

Abstract

When the sum of requested hydraulic power and requested travel power is greater than the sum of the engine power that can be outputted by an engine (1) and the electric discharge power that can be discharged by an electricity storage device (3), the actual power of a hydraulic pump (9) is increased from the value thereof at the time of the request toward the requested hydraulic power, while a predetermined limit is imposed; and while the predetermined limit is being imposed on the power of the hydraulic pump, the actual power of an electric travel motor is reduced by an amount no greater than the size of the predetermined limit from the value thereof at the time of the request. This configuration prevents adverse effects on ride comfort that are caused by the distribution of power to the hydraulic pump and the electric travel motor.

Description

technical field [0001] The present invention relates to work vehicles, and in particular to power distribution during compound actions. Background technique [0002] Among conventional work vehicles, there is a wheel loader (hereinafter referred to as a torque converter vehicle) that includes an engine, a hydraulic pump mechanically connected to the output shaft of the engine, and hydraulic fluid supplied from the hydraulic pump. An operating hydraulic actuator and a torque converter (hereinafter, referred to as a torque converter) type automatic transmission mechanically connected to an output shaft of the engine. In a torque converter vehicle, the engine power is transmitted through the automatic transmission, [0003] The propeller shaft, differential gear, and drive shaft are transmitted to the wheels for driving. In addition, the front mechanism is operated by the expansion and contraction of the hydraulic actuator, and the excavation, loading and transportation of sa...

AI Technical Summary

Problems solved by technology

[0014] However, in the hybrid construction machine described in Japanese Patent Application Laid-Open No. 2007-247230, the speed of change in power supply and power consumption is not necessarily considered sufficiently. When one of the hydraulic pump and the electric motor starts to operate first, the other power consumption If the total power supply is insufficient due to the increase, there is a possibility that the power of the one that operates first will decrease sharply

If this situation is applied to a wheel loader, when the hydraulic actuator is actuated during travel, there is a possibility that a sudden reduction in travel power, which is not present in conventional wheel loaders, may occur. There is a possibility that the ride quality may deteriorate

[0015] In addition, in a hybrid construction machine having a control mechanism described in JP-A-2009-216058, it is described that a generator motor is mainly used as a motor for assisting an engine. may not be adequately described