Damper operation control device and damper operation control method for working vehicle

Patent metadata

Field	Value
Publication number	US-9644339-B2
Application number	US-201113581833-A
Country	US
Kind code	B2
Filing date	Mar 1, 2011
Priority date	Mar 5, 2010
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A damper operation control device of a working vehicle, includes: a boom pivotably supported on a vehicle body; a bucket pivotably supported on a tip end of the boom; a lift cylinder which drives the boom; an accumulator connected to the lift cylinder through a branched oil passage; a switching valve connected to the branched oil passage between the lift cylinder and the accumulator, the switching valve switching between a connected state and a disconnected state between the lift cylinder and the accumulator; and a controller which performs switch control of the switching valve, wherein the controller includes: a state detecting unit which detects whether the bucket is in a loaded state; and a switching valve control unit which switches the switching valve to the connected state when the state detecting unit detects that the bucket is in the loaded state.

First claim

The invention claimed is:

1. A damper operation control device of a working vehicle, comprising:
a boom pivotably supported on a vehicle body;
a bucket pivotably supported on a tip end of the boom;
a lift cylinder which drives the boom;
an accumulator connected to the lift cylinder through a branched oil passage;
a switching valve connected to the branched oil passage between the lift cylinder and the accumulator, the switching valve switching between a connected state and a disconnected state between the lift cylinder and the accumulator;
a transmission for driving; and
a controller which performs switch control of the switching valve,
wherein
the controller includes:
a state detecting unit which detects whether the bucket is in a loaded state based on at least one of the bottom pressure of the lift cylinder, the attitude angle of the boom, the direction of the bucket, and a shift operation signal for operating the transmission; and
a switching valve control unit which
switches the switching valve to the connected state when the working vehicle travels at a speed not lower than a predetermined speed when the state detecting unit detects that the bucket is in a state other than the loaded state, and
switches the switching valve to the connected state even when the working vehicle travels at a speed lower than the predetermined speed when the state detecting unit at least determines that an attitude angle of the boom is below a horizontal plane and detects that the bucket is in the loaded state, and
the switching valve control unit switches the switching valve to the disconnected state when the shift operation signal indicates a predetermined stage which is a forward first speed stage or gear at a time of an excavation work.

2. The damper operation control device of the working vehicle according to claim 1 , wherein
the state detecting unit detects a transition state of at least an unladen state, a state during excavation work, and the loaded state as a working state of the working vehicle, and
the switching valve control unit switches the switching valve to the connected state when the working state of the working vehicle is the loaded state.

3. The damper operation control device of the working vehicle according to claim 1 , wherein the switching valve control unit switches the switching valve to the disconnected state when the boom is detected to be controlled to be in a predetermined attitude.

4. The damper operation control device of the working vehicle according to claim 1 , wherein the switching valve control unit switches the switching valve to the disconnected state based on an operation amount of an operating lever which operates a direction of the bucket, and/or an operation amount of an operating lever which operates an attitude of the boom.

5. The damper operation control device of the working vehicle according to claim 1 , wherein
the switching valve control unit switches the switching valve to the connected state when a bucket lever stroke of a bucket lever to operate a direction of the bucket is not smaller than a predetermined threshold stroke.

6. A damper operation control method for a working vehicle, the
working vehicle including:
a boom pivotably supported on a vehicle body;
a bucket pivotably supported on a tip end of the boom;
a lift cylinder which drives the boom through a branched oil passage;
an accumulator connected to the lift cylinder;
a switching valve connected to the branched oil passage between the lift cylinder and the accumulator, the switching valve switching between a connected state and a disconnected state between the lift cylinder and the accumulator;
a transmission for driving; and
a controller which performs switch control of the switching valve, the method comprising:
detecting, by a controller, whether the bucket is in a loaded state based on at least one of the bottom pressure of the lift cylinder, the attitude angle of the boom, the direction of the bucket, and a shift operation signal for operating the transmission; and
switching, by the controller, the switching valve to
the connected state when the working vehicle travels at a speed not lower than a predetermined speed which is a forward first speed stage or gear when the state detecting unit at least determines that an attitude angle of the boom is below a horizontal plane and detects that the bucket is in a state other than the loaded state, and switching the switching valve to
the connected state even when the working vehicle travels at a speed lower than the predetermined speed when the state detecting unit detects that the bucket is in the loaded state.

7. The damper operation control method according to claim 6 , wherein
the working vehicle further includes a transmission for driving,
the detecting includes detecting a transition state of at least an unladen state, a state during excavation work, and the loaded state as a working state of the working vehicle and detecting that a current working state of the working vehicle is the loaded state when a bottom pressure of the lift cylinder is detected to be not lower than predetermined unladen pressure for determining that a burden is not loaded in the bucket and an angle of the boom is detected to be smaller than a predetermined angle set in advance or when the bottom pressure of the lift cylinder is detected to be not lower than the predetermined unladen pressure and a direction of the bucket is detected to be horizontal or above a horizontal plane in a case that the current working state of the working vehicle is the unladen state, or when an operation signal to the transmission is detected to be other than forward in a case that the current working state of the working vehicle is the state during the excavation work.

8. The damper operation control method according to claim 6 , further comprising: detecting whether the boom is controlled to be in a predetermined attitude and switching the switching valve to the disconnected state when the boom is detected to be not controlled to be in the predetermined attitude.

9. The damper operation control method according to claim 6 , further comprising: switching the switching valve to the disconnected state when the transmission is in a predetermined stage.

10. A damper operation control device of a working vehicle, comprising:
a boom pivotably supported on a vehicle body;
a bucket pivotably supported on a tip end of the boom;
a lift cylinder which drives the boom;
an accumulator connected to the lift cylinder through a branched oil passage;
a switching valve connected to the branched oil passage between the lift cylinder and the accumulator, the switching valve switching between a connected state and a disconnected state between the lift cylinder and the accumulator;
a transmission for driving; and
a controller which performs switch control of the switching valve,
wherein
the controller includes:
a state detecting unit which detects whether the bucket is in a loaded state based on at least one of the bottom pressure of the lift cylinder, the attitude angle of the boom, the direction of the bucket, and a shift operation signal for operating the transmission; and
a switching valve control unit which switches the switching valve to the connected state when the working vehicle travels at a speed not lower than a predetermined speed when the state detecting unit detects that the bucket is in a state other than the loaded state, and switches the switching valve to the connected state even when the working vehicle travels at a speed lower than the predetermined speed when the state detecting unit at least determines that an attitude angle of the boom is below a horizontal pla

Assignees

• Wada Minoru
• Ota Toshuki
• Komatsu Mfg Co Ltd

Inventors

• Wada Minoru
• Ota Toshiyuki

Classifications

• E02F9/2217

  with energy recovery arrangements, e.g. using accumulators, flywheels · CPC title

• E02F9/2207

  for reducing or compensating oscillations · CPC title

• E02F3/434 Primary

  providing automatic sequences of movements, e.g. automatic dumping or loading, automatic return-to-dig · CPC title