CONSTRUCTION MACHINE

• US 20130319786A1
• Filed: 03/05/2012
• Published: 12/05/2013
• Est. Priority Date: 03/15/2011
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Hyodo, Koji, Tanaka, Tetsuji, Kikuchi, Keigo, Aoki, Isamu
• Granted Patent: US 9,255,386 B2
• Time in Patent Office: Days
• US Class Current: 180/306
• CPC Class Codes: B60H 1/00378 for tractor or load vehicle cabins
• CPC Class Codes: B60H 1/00828 Ventilators, e.g. speed control B60H1/00864 takes precedence
• CPC Class Codes: B60H 1/3205 Control means therefor
• CPC Class Codes: B60H 2001/3251 of the refrigerant at a condensing unit
• CPC Class Codes: E02F 9/0866 Engine compartment, e.g. heat exchangers, exhaust filters, cooling devices, silencers, mufflers, position of hydraulic pumps in the engine compartment
• CPC Class Codes: E02F 9/0875 Arrangement of valve arrangements on superstructures arrangement of hydraulic hoses E02F9/2275 takes precedence; valves per se E02F9/2267
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/22 Hydraulic or pneumatic drives for dipper or bucket arm position control E02F3/43, for blade position control for graders E02F3/844; for turntables E02F9/121; for fork-lift trucks B66F9/22
• CPC Class Codes: E02F 9/226 Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
• CPC Class Codes: F28F 27/00 Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus control arrangements in general G05

Abstract

A construction machine includes a condenser 24 for cooling refrigerant for an air conditioner; a fan 21 for cooling the condenser 24 by using forward cooling air produced during normal-rotation drive; other cooled objects such as a radiator 25 and the like disposed under the lee of the forward cooling air with respect to the condenser 24; a refrigerant pressure detector 27 for detecting the pressure of the refrigerant flowing in the condenser 24; and a controller 136 for executing reverse-rotation stop processing for returning the fan 21 to the normal-rotation drive when the pressure P of the air conditioner refrigerant detected by the refrigerant pressure detector 27 reaches a preset normal-rotation return pressure P1 during reverse-rotation drive of the fan 21. Thus, the lowering of the cooling effect of an air conditioner can be suppressed while reducing the burden of cleaning an engine room.

Claims

1. A construction machine comprising:

a condenser for cooling a refrigerant for an air conditioner;

a fan for cooling the condenser by using forward cooling air produced during normal-rotation drive;

another cooled object disposed under the lee of the forward cooling air with respect to the condenser;

a refrigerant pressure detector for detecting the pressure of the refrigerant flowing in the condenser; and

a controller for executing reverse-rotation stop processing for returning the fan to normal-rotation drive when the pressure of the refrigerant detected by the refrigerant pressure detector reaches a preset normal-rotation return pressure during reverse-rotation drive of the fan.

2. The construction machine according to claim 1,

wherein the controller executes, before the execution of the reverse-rotation stop processing, forced reverse-rotation processing for continuing the reverse-rotation drive of the fan regardless of the detected pressure of the refrigerant until a predetermined forced reverse-rotation period elapses after the reverse-rotation of the fan has been started.

3. The construction machine according to claim 2,

wherein the controller has a function to execute automatic reverse-rotation processing in which the fan is driven for reverse rotation for a preset reverse-rotation period at regular time intervals, and during the execution of the automatic reverse-rotation processing, the controller sequentially executes the forced reverse-rotation processing and the reverse-rotation stop processing and returns the fan to the normal-rotation drive after the reverse-rotation drive period elapses with the fan remaining driven for reverse rotation.

4. The construction machine according to claim 2, comprising;

a forced period setter for setting the forced reverse-rotation period or a connecting portion to which the forced period setter is connected.

5. The construction machine according to claim 2, comprising:

changeover means for changing over validity and invalidity of the reverse-rotation stop processing.

6. The construction machine according to claim 2, further comprising:

an engine;

a hydraulic pump for driving the engine;

a hydraulic actuator driven by hydraulic operating fluid delivered from the hydraulic pump;

a hydraulic operating fluid temperature detector for detecting temperature of the hydraulic operating fluid;

a transmission for changing vehicle speed;

a torque converter for transmitting drive force of the engine to the transmission;

a torque converter oil temperature detector for detecting temperature of torque converter oil, which is a power transmission medium of the torque converter;

a radiator as the other cooled object for cooling the cooling water of the engine; and

an engine control unit for controlling and monitoring the engine;

wherein the controller returns the fan to the normal-rotation drive regardless of elapse time after the start of the reverse rotation of the fan or the detection pressure of the refrigerant if any one of detection values of the hydraulic operating fluid temperature detector and the torque converter oil temperature detector reaches a corresponding one of respective preset values, or if the controller receives a signal for warning overheat of the engine from the engine control unit, during the reverse-rotation drive of the fan.